Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium si...Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium silicates during the first cycle.In this work,we modify SiO_(x) by solid-phase Mg doping reaction using low-cost Mg powder as a reducing agent.We show that Mg reduces SiO_(2) in SiO_(x) to Si and forms MgSiO_(3) or Mg_(2)SiO_(4).The MgSiO_(3) or Mg_(2)SiO_(4) are mainly distributed on the surface of SiO_(x),which suppresses the irreversible lithium-ion loss and enhances the ICE of SiO_(x).However,the formation of MgSiO_(3) or Mg_(2)SiO_(4) also sacrifices the capacity of SiO_(x).Therefore,by controlling the reaction process between Mg and SiO_(x),we can tune the phase composition,proportion,and morphology of the Mg-doped SiO_(x) and manipulate the performance.We obtain samples with a capacity of 1226 mAh g^(–1) and an ICE of 84.12%,which show significant improvement over carbon-coated SiO_(x) without Mg doping.By the synergistical modification of both Mg doping and prelithiation,the capacity of SiO_(x) is further increased to 1477 mAh g^(–1) with a minimal compromise in the ICE(83.77%).展开更多
Initial Coulombic efficiency(ICE)has been widely adopted in battery research as a quantifiable indicator for the lifespan,energy density and rate performance of batteries.Hard carbon materials have been accepted as a ...Initial Coulombic efficiency(ICE)has been widely adopted in battery research as a quantifiable indicator for the lifespan,energy density and rate performance of batteries.Hard carbon materials have been accepted as a promising anode family for sodium-ion batteries(SIBs)owing to their outstanding performance.However,the booming application of hard carbon anodes has been significantly slowed by the low ICE,leading to a reduced energy density at the cell level.This offers a challenge to develop high ICE hard carbon anodes to meet the applications of high-performance SIBs.Here,we discuss the definition and factors of ICE and describe several typical strategies to improve the ICE of hard carbon anodes.The strategies for boosting the ICE of such anodes are also systematically categorized into several aspects including structure design,surface engineering,electrolyte optimization and pre-sodiation.The key challenges and perspectives in the development of high ICE hard carbon anodes are also outlined.展开更多
Hard carbon(HC)is a promising anode material for sodium ion batteries(SIBs),whereas inferior initial coulombic efficiency(ICE)severely limits its practical application.In the present work,we propose an in situ electro...Hard carbon(HC)is a promising anode material for sodium ion batteries(SIBs),whereas inferior initial coulombic efficiency(ICE)severely limits its practical application.In the present work,we propose an in situ electrochemical presodiation approach to improve ICE by mixing sodium biphenyl(Na-Bp)dimethoxyethane(DME)solution with DME-based ether electrolyte.A solid electrolyte interface(SEI)could be formed beforehand on the HC electrode and Na^(+)was absorbed to nanopores and graphene stacks,compensating for the sodium loss and preventing electrolyte decomposition during the initial charge and discharge cycle.By this way,the ICE of half-cells was increased to nearly 100%and that of full-cells from 45%to 96%with energy density from 132.9 to 230.5 W h kg^(-1).Our work provides an efficient and facile method for improving ICE,which can potentially promote the practical application of HCbased materials.展开更多
In practical lithium-sulfur batteries(LSBs),the shuttle effect and Li cycling coulombic efficiency(CE) are strongly affected by the physicochemical properties of solid electrolyte interphase(SEI).LiNO_(3) is widely us...In practical lithium-sulfur batteries(LSBs),the shuttle effect and Li cycling coulombic efficiency(CE) are strongly affected by the physicochemical properties of solid electrolyte interphase(SEI).LiNO_(3) is widely used as an additive in electrolytes to build a high-quality SEI,but its self-sacrificial nature limits the ability to mitigate the shuttle effect and stabilize Li anode during long-term cycling.To counteract LiNO_(3) consumption during long-term cycling without using a high initial concentration,inspired by sustainedrelease drugs,we encapsulated LiNO_(3) in lithiated Nafion polymer and added an electrolyte co-solvent(1,1,2,2-tetrafluoroethylene 2,2,2-trifluoromethyl ether) with poor LiNO_(3) solubility to construct highquality and durable F-and N-rich SEI.Theoretical calculations,experiments,multiphysics simulations,and in-situ observations confirmed that the F-and N-rich SEI can modulate lithium deposition behavior and allow persistent repair of SEI during prolonged cycling.Hence,the F-and N-rich SEI improves the Li anode cycling CE to 99.63% and alleviates the shuttle effect during long-term cycling.The lithium anode with sustainable F-and N-rich SEI shows a stable Li plating/stripping over 2000 h at 1 mA cm^(-2).As expected,Li‖S full cells with this SEI achieved a long lifespan of 250 cycles,far exceeding cells with a routine SEI.The Li‖S pouch cell based on F-and N-rich SEI also can achieve a high energy density of about300 Wh kg^(-1) at initial cycles.This strategy provides a novel design for high-quality and durable SEls in LSBs and may also be extendable to other alkali metal batteries.展开更多
Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries;however,its abundant defects or micropores generally capture K ions,thus resulting in high irreversible capacity...Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries;however,its abundant defects or micropores generally capture K ions,thus resulting in high irreversible capacity with low initial Coulombic efficiency(ICE)and limited practical application.Herein,pore engineering via a facile self-etching strategy is applied to achieve mesoporous carbon(meso-C)nanowires with interconnected framework.Abundant and evenly distributed mesopores could provide short K^+ pathways for its rapid diffusion.Compared to microporous carbon with highly disordered structure,the meso-C with Zn-catalyzed short-range ordered structure enables more K^+to reversibly intercalate into the graphitic layers.Consequently,the mesoC shows an increased capacity by ~100 mAh g^-1 at 0.1 A g^-1,and the capacity retention is 70.7% after 1000 cycles at 1 A g^-1.Multiple in/ex situ characterizations reveal the reversible structural changes during the charging/discharging process.Particularly,benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less defects,the meso-C generates less irreversible capacity with high ICE up to 76.7%,one of the best reported values so far.This work provides a new perspective that mesopores engineering can effectively accelerate K^+ diffusion and enhance K^+ adsorption/intercalation storage.展开更多
The application of Sb_(2)S_(3)with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency(ICE).In this work,natural ...The application of Sb_(2)S_(3)with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency(ICE).In this work,natural stibnite modified by carbon dots(Sb_(2)S_(3)@xCDs)is elaborately designed with high ICE.Greatly,chemical processes of local oxidation–partial reduction–deep coupling for stibnite reduction of CDs are clearly demonstrated,confirmed with in situ high-temperature X-ray diffraction.More impressively,the ICE for lithium-ion batteries(LIBs)is enhanced to 85%,through the effect of oxygen-rich carbon matrix on C–S bonds which inhibit the conversion of sulfur to sulfite,well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations.Not than less,it is found that Sb–O–C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation.As a result,the optimal sample delivers a tremendous reversible capacity of 660 mAh g^(−1)in LIBs at a high current rate of 5 A g^(−1).This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides,especially for improving the ICE.展开更多
The soaring demand for electrical energy storage technologies stimulated by advanced portable devices, prospering electric vehicles, and large-scale grid storage applications have triggered explosive research on Li me...The soaring demand for electrical energy storage technologies stimulated by advanced portable devices, prospering electric vehicles, and large-scale grid storage applications have triggered explosive research on Li metal battery (LMB), which has been widely acknowledged as the most promising energy storage technology of the future that can break the energy-density bottleneck of the state-of-art lithium-ion battery (LIB) technology [1,2].展开更多
Low initial Coulombic efficiency (ICE) is an important impediment to practical application of Li-rich layered oxides (LLOs), which is due to the irreversible oxygen release. It is generally considered that surface oxy...Low initial Coulombic efficiency (ICE) is an important impediment to practical application of Li-rich layered oxides (LLOs), which is due to the irreversible oxygen release. It is generally considered that surface oxygen vacancies are conducive to the improvement of ICE of LLOs. To reveal the relation of oxygen vacancies and ICE, sample PLO (Li-Mn-Cr-O) and its treated product (TLO) are comprehensive investigated in this work. During the treated process, part of oxygen atoms return to original constructed vacancies. It makes oxygen vacancies in sample TLO much poorer than those in sample PLO, and induces the formation of Li-poor spinel-layered integrated structure. Electrochemical measurement indicates the ICE of sample PLO is only 80.8%, while sample TLO is almost full reversible with the ICE of ~97.1%. In term of high-energy X-ray diffraction, scanning transmission electron microscopy, X-ray photoelectron spectroscopy and synchrotron hard/soft X-ray absorption spectroscopy, we discover that the ICE is difficult to be improved significantly just by building oxygen vacancies. LLOs with high ICE not only have to construct suitable oxygen vacancies, but also require other components with Li-poor structure to stabilize oxygen. This work provides deep insight into the mechanism of high ICE, and will contribute to the design and development of LLOs for next-generation high-energy lithium-ion batteries.展开更多
Silicon monoxide(SiO)has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries.To enhance the initial Coulombic efficiencies(ICE)and cycle stability of SiO-based anod...Silicon monoxide(SiO)has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries.To enhance the initial Coulombic efficiencies(ICE)and cycle stability of SiO-based anodes,a new facile composition and electrode design strategy have been adapted to fabricate a SiO-Sn-Co/graphite(G)anode.It achieves a unique structure where tiny milled SiO-Sn-Co particles are dispersed among two graphite layers.In this hybrid electrode,Sn-Co alloys promoted Li;extraction kinetics,and the holistic reversibility of SiO and graphite enhanced the electrical conductivity.The SiO-Sn-Co/G electrode delivered an average ICE of 77.6%and a reversible capacity of 640 mAh g^(-1)at 800 mA g^(-1),and the capacity retention was above 98%after 100 cycles,which was much higher than that of the SiO with an ICE of 55.3%and a capacity retention of 50%.These results indicated that this was reliable method to improve the reversibility and cycle ability of the SiO anode.Furthermore,based on its easy and feasible fabrication process,it may provide a suitable choice to combine other alloy anodes with the graphite anode.展开更多
Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produ...Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically important.Herein,a nanostructured graphite composed of multi-walled carbon nanotubes(MWCNTs)and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework(MOF)and carbon source.The high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency(ICE)exceed 80%,and the three-dimensional(3D)conductive network ensures a specific capacity of 234 mAh·g^(−1)after 1000 cycles at a high current density of 500 mA·g^(−1).In addition,the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction(XRD)and in situ Raman spectroscopy,and its practicality is also proved by the voltage of the full cells.This work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.展开更多
Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is imp...Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is impeded by their low initial Coulombic efficiency and rapid voltage decay.Herein,a V-doped layered-spinel coherent layer is constructed on the surface of a Co-free LRMO through a simple treatment with NH_(4)VO_(3).The layered-spinel coherent layer with 3D ion channels enhanced Li+diffusion efficiency,mitigates surface-inter-face reactions and suppresses irreversible oxygen release.Notably,V-doping significantly reduces the Bader charge of oxygen atoms,thereby impeding excessive oxidation of oxygen ions and further enhancing the stability of O-redox.The modified LRMO exhibites a remarkable initial Coulombic efficiency of 91.6%,signifi-cantly surpassing that of the original LRMO(74.4%).Furthermore,the treated sample showes an impressive capacity retention rate of 91.9%after 200 cycles,accompanied by a voltage decay of merely 0.47 mV per cycle.The proposed treatment approach is straightforward and significantly improves the initial Coulombic efficiency,voltage stability,and capacity stability of LRMO cathode materials,thus holding considerable promise for the development of high-energy Li-ion batteries.展开更多
Due to the abundant sodium reserves and high safety,sodium ion batteries(SIBs)are foreseen a promising future.While,hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advan...Due to the abundant sodium reserves and high safety,sodium ion batteries(SIBs)are foreseen a promising future.While,hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages.However,the unsatisfactory initial coulombic efficiency(ICE)is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application.Herein,with spherical nano SiO_(2)as pore-forming agent,gelatin and polytetrafluoroethylene as carbon sources,a multi-porous carbon(MPC)material can be easily obtained via a co-pyrolysis method,by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases.As a result,the MPC anode exhibited remarkable ICE of 83%and a high rate capability(208 m Ah/g at 5 A/g)when used in sodium-ion half cells.Additionally,coupling with Na3V2(PO4)3as the cathode to assemble full cells,the as-fabricated MPC//NVP full cell delivered a good rate capability(146 m Ah/g at 5 A/g)as well,implying a good application prospect the MPC anode has.展开更多
Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great effort...Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great efforts have been devoted to developing high-performance carbonaceous materials with high capacity,long life span,and excellent rate capability,the low initial Coulombic efficiency(ICE)of high-capacity carbonaceous materials seriously limits their practical applications.Various methods have been successfully exploited,and a revolutionary impact has been achieved through the utilization of different techniques.Different carbonaceous materials possess different ion storage mechanisms,which means that the initial capacity loss may vary.However,there has rarely been a special review about the origins of and progress in the ICE for carbonaceous materials from the angle of the crystal structure.Hence,in this review,the structural differences between and ion storage mechanisms of various carbonaceous materials are first introduced.Then,we deduce the correlative factors of low ICE and thereafter summarize the proposed strategies to address these issues.Finally,some challenges,perspectives,and future directions on the ICE of carbonaceous materials are given.This review will provide deep insights into the challenges of improving the ICE of carbonaceous anodes for high-energy Li/Na-ion batteries,which will greatly contribute to their commercialization process.展开更多
The low initial Coulombic efficiency(ICE)of SiOx anode caused by the irreversible generation of LiySiOz and Li20 during lithiation process limits its application for high energy-density lithium-ion batteries.Herein,we...The low initial Coulombic efficiency(ICE)of SiOx anode caused by the irreversible generation of LiySiOz and Li20 during lithiation process limits its application for high energy-density lithium-ion batteries.Herein,we report a molten-salt-induced thermochemical.prelithiation strategy for regulating the electrochemically active Si/O ratio of SiOx and thus enhancing ICE through thermal treatment of pre-synthesized LiNH2-coated SiOx in molten LiCl at 700℃.Bulk SiOx micro-particle was transformed into pomegranatelike prelithiated micro-cluster composite(M-Li-SiOx)with SiOx core and outer nano-sized agglomerates consisting of Li2Si20s,SiO2,and Si.Through the analysis of the reaction intermediates,molten-UC!could initiate reactions and promote mass transfer by the continuous extraction of oxygen component from SiOx particle inner in the form of inert Li2Si20s and SiO2 nanotubes to realize the.prelithiation.The degree of prelithiation can be regulated by adjusting the coating amount of LiNH2 layer,and the resulted M-Li-SiOx displays a prominent improvement of ICE from 58.73%to 88.2%.The graphite/M-Li-SiOx(8:2)composite electrode delivers a.discharge capacity of 497.29 mAh·g^(-1) with an ICE of 91.79%.By pairing graphite/M-Li-SiOx anode and LiFeP04 cathode in a full-cell an enhancement of energy density of 37.25%is realized compared with the full-cell containing graphite/SiOx anode.Furthermore,,ex-situ X-ray photoelectron spectroscopy(XPS)/Raman/X-ray diffraction(XRD)and related electrochemical measurements reveal the SiOx core and Si of M-Li-SiOx participate in the lithiation,and pre-generated Li2Si20s with u+diffusivity and pomegranate-like.structure reduces the reaction resistance and interface impedance of the solid electrolyte interphase(SEI)film.展开更多
Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgentl...Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of HC.In this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.展开更多
Sodium-ion batteries(SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+io...Sodium-ion batteries(SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+ions consumption during the first cycle of charge/discharge process(due to the formation of the solid electrolyte interface(SEI) on the electrode surface and other irreversible reactions) is the factor that determines high performance SIBs and largely reduces the capacity of the full cell SIBs. Thus, the initial coulombic efficiency(ICE) of SIBs for both anode and cathode materials, is a key parameter for high performance SIBs, and the point is to increase the transport rate of the Na+ions. Therefore, developing SIBs with high ICE and rate performance becomes vital to boost the commercialization of SIBs. Here we provide a review on the methods to improve the ICE and the rate performance, by summarizing some methods of improving the ICE and rate performance of the anode and cathode materials for SIBs, and end by a conclusion with some perspectives and recommendations.展开更多
All-solid-state lithium batteries(ASSLBs)employ high-capacity lithium(Li)metal as the anode and exhibit a higher energy density than that of conventional Li-ion batteries.However,the problems arose from the Li dendrit...All-solid-state lithium batteries(ASSLBs)employ high-capacity lithium(Li)metal as the anode and exhibit a higher energy density than that of conventional Li-ion batteries.However,the problems arose from the Li dendrites induce severely parasitic reaction between Li and electrolytes,leading to low coulombic efficiency(CE)and poor cyclic stability.Herein,a poly(vinylidene-co-hexafluoropropylene)/lithium nitrate(PVDF-HFP/LiNO_(3),marked as PFH/LN)artificial layer is employed to modified Li and achieve high CE ASSLBs with polyethylene oxide-Li_(6.4) La_(3)Zr_(1.4)Ta_(0.6)O_(12)(PEO-LLZTO)electrolyte.LN serves as a functionalized additive to facilitate the formation of a robust solid electrolyte interface(SEI),effi-ciently suppressing the formation of Li dendrites.Additionally,LN as a“binder”effectively links PFH with Li,providing good contact.PFH possesses high mechanical strength and moderate flexibility,which can not only physically inhibit the growth of Li dendrites,but also maintain the structural integrity of arti-ficial layer over long-term cycles.Finally,Li/Li cells with such artificial layer demonstrate ultralong cycle life of 1800 and 1000 h under 0.2 and 0.4 mA cm^(-1),respectively.Furtherly,high CE can be achieved when applied in both LiFePO 4 full cells and Li-Cu half cells.This work offers a facile and efficient strategy to greatly promote CE in PEO-based ASSLBs.展开更多
Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages ...Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces,thus significantly degrading the cycling lifespan and decreasing the specific capacity.Here,we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl)borate(TFEB),based on 3,3,3-fluoroethylmethylcarbonate(FEMC)and fluoroethylene carbonate(FEC),which enables stable cycling of high nickel cathode(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),NMC811)under a cut-off voltage of 4.7 V in Li metal batteries.The electrolyte not only shows the fire-extinguishing properties,but also inhibits the transition metal dissolution,the gas production,side reactions on the cathode side.Therefore,the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode,delivering a specific capacity>220 mA h g^(-1),an average Coulombic efficiency>99.6%and capacity retention>99.7%over 100 cycles.展开更多
Sodium-ion batteries(SIBs)are expected to offer affordability and high energy density for large-scale energy storage system.However,the commercial application of SIBs is hurdled by low initial coulombic efficiency(ICE...Sodium-ion batteries(SIBs)are expected to offer affordability and high energy density for large-scale energy storage system.However,the commercial application of SIBs is hurdled by low initial coulombic efficiency(ICE),continuous Na loss during long-term operation,and low sodium-content of cathode materials.In this scenario,presodiation strategy by introducing an external sodium reservoir has been rationally proposed,which could supplement additional sodium ions into the system and thereby markedly improve both the cycling performance and energy density of SIBs.In this review,the significance of presodiation is initially introduced,followed by comprehensive interpretation on technological properties,underlying principles,and associated approaches,as well as our perspectives on present inferiorities and future research directions.Overall,this contribution outlines a distinct pathway towards the presodiation methodology,of significance but still in its nascent phase,which may inspire the targeted guidelines to explore new chemistry in this field.展开更多
Green energy storage devices play vital roles in reducing fossil fuel emissions and achieving carbon neutrality by 2050.Growing markets for portable electronics and electric vehicles create tremendous demand for advan...Green energy storage devices play vital roles in reducing fossil fuel emissions and achieving carbon neutrality by 2050.Growing markets for portable electronics and electric vehicles create tremendous demand for advanced lithium-ion batteries(LIBs)with high power and energy density,and novel electrode material with high capacity and energy density is one of the keys to next-generation LIBs.Silicon-based materials,with high specific capacity,abundant natural resources,high-level safety and environmental friendliness,are quite promising alternative anode materials.However,significant volume expansion and redundant side reactions with electrolytes lead to active lithium loss and decreased coulombic efficiency(CE)of silicon-based material,which hinders the commercial application of silicon-based anode.Prelithiation,preembedding extra lithium ions in the electrodes,is a promising approach to replenish the lithium loss during cycling.Recent progress on prelithiation strategies for silicon-based anode,including electrochemical method,chemical method,direct contact method,and active material method,and their practical potentials are reviewed and prospected here.The development of advanced Si-based material and prelithiation technologies is expected to provide promising approaches for the large-scale application of silicon-based materials.展开更多
基金supported by the National Natural Science Foundation(52232009)the National Natural Science Foundation for Distinguished Young Scholar(52125404)+1 种基金the National Youth Talent Support Program,“131”First Level Innovative Talents Training Project in Tianjinthe Tianjin Natural Science Foundation for Distinguished Young Scholar(18JCJQJC46500).
文摘Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium silicates during the first cycle.In this work,we modify SiO_(x) by solid-phase Mg doping reaction using low-cost Mg powder as a reducing agent.We show that Mg reduces SiO_(2) in SiO_(x) to Si and forms MgSiO_(3) or Mg_(2)SiO_(4).The MgSiO_(3) or Mg_(2)SiO_(4) are mainly distributed on the surface of SiO_(x),which suppresses the irreversible lithium-ion loss and enhances the ICE of SiO_(x).However,the formation of MgSiO_(3) or Mg_(2)SiO_(4) also sacrifices the capacity of SiO_(x).Therefore,by controlling the reaction process between Mg and SiO_(x),we can tune the phase composition,proportion,and morphology of the Mg-doped SiO_(x) and manipulate the performance.We obtain samples with a capacity of 1226 mAh g^(–1) and an ICE of 84.12%,which show significant improvement over carbon-coated SiO_(x) without Mg doping.By the synergistical modification of both Mg doping and prelithiation,the capacity of SiO_(x) is further increased to 1477 mAh g^(–1) with a minimal compromise in the ICE(83.77%).
基金supported by the National Key R&D Program of China(2018YFE0201701 and 2018YFA0209401)the National Natural Science Foundation of China(Grant nos.22088101,U21A20329,21733003 and 21975050)+1 种基金the Science and Technology Commission of Shanghai Municipality(19JC1410700)Program of Shanghai Academic Research Leader(21XD1420800)。
文摘Initial Coulombic efficiency(ICE)has been widely adopted in battery research as a quantifiable indicator for the lifespan,energy density and rate performance of batteries.Hard carbon materials have been accepted as a promising anode family for sodium-ion batteries(SIBs)owing to their outstanding performance.However,the booming application of hard carbon anodes has been significantly slowed by the low ICE,leading to a reduced energy density at the cell level.This offers a challenge to develop high ICE hard carbon anodes to meet the applications of high-performance SIBs.Here,we discuss the definition and factors of ICE and describe several typical strategies to improve the ICE of hard carbon anodes.The strategies for boosting the ICE of such anodes are also systematically categorized into several aspects including structure design,surface engineering,electrolyte optimization and pre-sodiation.The key challenges and perspectives in the development of high ICE hard carbon anodes are also outlined.
基金supported by the National Natural Science Foundation of China,China(51932011,52072411,52104285)the Natural Science Foundation of Hunan Province,China(2021JJ20060)+1 种基金the Science and Technology Innovation Program of Hunan Province,China(2021RC3001)the Fundamental Research Funds for the Central Universities,China(202044011)。
文摘Hard carbon(HC)is a promising anode material for sodium ion batteries(SIBs),whereas inferior initial coulombic efficiency(ICE)severely limits its practical application.In the present work,we propose an in situ electrochemical presodiation approach to improve ICE by mixing sodium biphenyl(Na-Bp)dimethoxyethane(DME)solution with DME-based ether electrolyte.A solid electrolyte interface(SEI)could be formed beforehand on the HC electrode and Na^(+)was absorbed to nanopores and graphene stacks,compensating for the sodium loss and preventing electrolyte decomposition during the initial charge and discharge cycle.By this way,the ICE of half-cells was increased to nearly 100%and that of full-cells from 45%to 96%with energy density from 132.9 to 230.5 W h kg^(-1).Our work provides an efficient and facile method for improving ICE,which can potentially promote the practical application of HCbased materials.
基金partially supported by grants from the National Natural Science Foundation of China (52072099, 52102228)Team program of the Natural Science Foundation of Heilongjiang Province, China (TD2021E005)+1 种基金The National general entrepreneurial practice program (202210231088S)The National general innovation training program (202210231076)。
文摘In practical lithium-sulfur batteries(LSBs),the shuttle effect and Li cycling coulombic efficiency(CE) are strongly affected by the physicochemical properties of solid electrolyte interphase(SEI).LiNO_(3) is widely used as an additive in electrolytes to build a high-quality SEI,but its self-sacrificial nature limits the ability to mitigate the shuttle effect and stabilize Li anode during long-term cycling.To counteract LiNO_(3) consumption during long-term cycling without using a high initial concentration,inspired by sustainedrelease drugs,we encapsulated LiNO_(3) in lithiated Nafion polymer and added an electrolyte co-solvent(1,1,2,2-tetrafluoroethylene 2,2,2-trifluoromethyl ether) with poor LiNO_(3) solubility to construct highquality and durable F-and N-rich SEI.Theoretical calculations,experiments,multiphysics simulations,and in-situ observations confirmed that the F-and N-rich SEI can modulate lithium deposition behavior and allow persistent repair of SEI during prolonged cycling.Hence,the F-and N-rich SEI improves the Li anode cycling CE to 99.63% and alleviates the shuttle effect during long-term cycling.The lithium anode with sustainable F-and N-rich SEI shows a stable Li plating/stripping over 2000 h at 1 mA cm^(-2).As expected,Li‖S full cells with this SEI achieved a long lifespan of 250 cycles,far exceeding cells with a routine SEI.The Li‖S pouch cell based on F-and N-rich SEI also can achieve a high energy density of about300 Wh kg^(-1) at initial cycles.This strategy provides a novel design for high-quality and durable SEls in LSBs and may also be extendable to other alkali metal batteries.
基金supported by the National Natural Science Foundation of China (51832004, 21805219 and 51521001)the National Key Research and Development Program of China (2016YFA0202603)+2 种基金the Programme of Introducing Talents of Discipline to Universities (B17034)the Yellow Crane Talent (Science & Technology) Program of Wuhan CityFoshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHT2020-003)。
文摘Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries;however,its abundant defects or micropores generally capture K ions,thus resulting in high irreversible capacity with low initial Coulombic efficiency(ICE)and limited practical application.Herein,pore engineering via a facile self-etching strategy is applied to achieve mesoporous carbon(meso-C)nanowires with interconnected framework.Abundant and evenly distributed mesopores could provide short K^+ pathways for its rapid diffusion.Compared to microporous carbon with highly disordered structure,the meso-C with Zn-catalyzed short-range ordered structure enables more K^+to reversibly intercalate into the graphitic layers.Consequently,the mesoC shows an increased capacity by ~100 mAh g^-1 at 0.1 A g^-1,and the capacity retention is 70.7% after 1000 cycles at 1 A g^-1.Multiple in/ex situ characterizations reveal the reversible structural changes during the charging/discharging process.Particularly,benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less defects,the meso-C generates less irreversible capacity with high ICE up to 76.7%,one of the best reported values so far.This work provides a new perspective that mesopores engineering can effectively accelerate K^+ diffusion and enhance K^+ adsorption/intercalation storage.
基金financially supported by the National Natural Science Foundation of China (51904342, 52074359, U21A20284)Hunan Provincial Science and Technology Plan (2020JJ3048)the Science and Technology Innovation Program of Hunan Province (2021RC3014, 2020RC4005, 2019RS1004)
文摘The application of Sb_(2)S_(3)with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency(ICE).In this work,natural stibnite modified by carbon dots(Sb_(2)S_(3)@xCDs)is elaborately designed with high ICE.Greatly,chemical processes of local oxidation–partial reduction–deep coupling for stibnite reduction of CDs are clearly demonstrated,confirmed with in situ high-temperature X-ray diffraction.More impressively,the ICE for lithium-ion batteries(LIBs)is enhanced to 85%,through the effect of oxygen-rich carbon matrix on C–S bonds which inhibit the conversion of sulfur to sulfite,well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations.Not than less,it is found that Sb–O–C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation.As a result,the optimal sample delivers a tremendous reversible capacity of 660 mAh g^(−1)in LIBs at a high current rate of 5 A g^(−1).This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides,especially for improving the ICE.
基金supported by QIBEBT I201922, Dalian National Laboratory For Clean Energy (DNL), CASNational Natural Science Foundation of China (U1904216)。
文摘The soaring demand for electrical energy storage technologies stimulated by advanced portable devices, prospering electric vehicles, and large-scale grid storage applications have triggered explosive research on Li metal battery (LMB), which has been widely acknowledged as the most promising energy storage technology of the future that can break the energy-density bottleneck of the state-of-art lithium-ion battery (LIB) technology [1,2].
基金We thank the funding supports of the National Natural Science Foundation of China(Project Nos.51874104 and 52004070)the Key Technology and Supporting Platform of Genetic Engineering of Materials under States Key Project of Research and Development Plan of China(Project No.2016YFB0700600).The authors thank Cheng-Hao Chuang for the assistant with X-ray spectroscopy measurement.
文摘Low initial Coulombic efficiency (ICE) is an important impediment to practical application of Li-rich layered oxides (LLOs), which is due to the irreversible oxygen release. It is generally considered that surface oxygen vacancies are conducive to the improvement of ICE of LLOs. To reveal the relation of oxygen vacancies and ICE, sample PLO (Li-Mn-Cr-O) and its treated product (TLO) are comprehensive investigated in this work. During the treated process, part of oxygen atoms return to original constructed vacancies. It makes oxygen vacancies in sample TLO much poorer than those in sample PLO, and induces the formation of Li-poor spinel-layered integrated structure. Electrochemical measurement indicates the ICE of sample PLO is only 80.8%, while sample TLO is almost full reversible with the ICE of ~97.1%. In term of high-energy X-ray diffraction, scanning transmission electron microscopy, X-ray photoelectron spectroscopy and synchrotron hard/soft X-ray absorption spectroscopy, we discover that the ICE is difficult to be improved significantly just by building oxygen vacancies. LLOs with high ICE not only have to construct suitable oxygen vacancies, but also require other components with Li-poor structure to stabilize oxygen. This work provides deep insight into the mechanism of high ICE, and will contribute to the design and development of LLOs for next-generation high-energy lithium-ion batteries.
基金supported by the National Natural Science Foundation of China (No. 52071144, 51822104, 51831009, and 51621001)
文摘Silicon monoxide(SiO)has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries.To enhance the initial Coulombic efficiencies(ICE)and cycle stability of SiO-based anodes,a new facile composition and electrode design strategy have been adapted to fabricate a SiO-Sn-Co/graphite(G)anode.It achieves a unique structure where tiny milled SiO-Sn-Co particles are dispersed among two graphite layers.In this hybrid electrode,Sn-Co alloys promoted Li;extraction kinetics,and the holistic reversibility of SiO and graphite enhanced the electrical conductivity.The SiO-Sn-Co/G electrode delivered an average ICE of 77.6%and a reversible capacity of 640 mAh g^(-1)at 800 mA g^(-1),and the capacity retention was above 98%after 100 cycles,which was much higher than that of the SiO with an ICE of 55.3%and a capacity retention of 50%.These results indicated that this was reliable method to improve the reversibility and cycle ability of the SiO anode.Furthermore,based on its easy and feasible fabrication process,it may provide a suitable choice to combine other alloy anodes with the graphite anode.
基金the financial support from the National Key Research and Development Program of China(Nos.2022YFB2404300 and 2023YFB3809303)the National Natural Science Foundation of China(Nos.51832004 and 52127816)State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(No.WUT:2022-KF-4).
文摘Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically important.Herein,a nanostructured graphite composed of multi-walled carbon nanotubes(MWCNTs)and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework(MOF)and carbon source.The high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency(ICE)exceed 80%,and the three-dimensional(3D)conductive network ensures a specific capacity of 234 mAh·g^(−1)after 1000 cycles at a high current density of 500 mA·g^(−1).In addition,the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction(XRD)and in situ Raman spectroscopy,and its practicality is also proved by the voltage of the full cells.This work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.
基金Natural Science Research(Department of Education)Project of Higher Education Institutions in Guangdong Province(Grant No.2018KQNCX063)Applied Basic Research Fund of Guangdong Province(Grant No.2024B1515020071)+1 种基金National Natural Science Foundation of China(Grant Nos.52371217 and 52150410411)Guangdong Provincial Science and Technology Plan Project(Grant No.2023A0505020009)。
文摘Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is impeded by their low initial Coulombic efficiency and rapid voltage decay.Herein,a V-doped layered-spinel coherent layer is constructed on the surface of a Co-free LRMO through a simple treatment with NH_(4)VO_(3).The layered-spinel coherent layer with 3D ion channels enhanced Li+diffusion efficiency,mitigates surface-inter-face reactions and suppresses irreversible oxygen release.Notably,V-doping significantly reduces the Bader charge of oxygen atoms,thereby impeding excessive oxidation of oxygen ions and further enhancing the stability of O-redox.The modified LRMO exhibites a remarkable initial Coulombic efficiency of 91.6%,signifi-cantly surpassing that of the original LRMO(74.4%).Furthermore,the treated sample showes an impressive capacity retention rate of 91.9%after 200 cycles,accompanied by a voltage decay of merely 0.47 mV per cycle.The proposed treatment approach is straightforward and significantly improves the initial Coulombic efficiency,voltage stability,and capacity stability of LRMO cathode materials,thus holding considerable promise for the development of high-energy Li-ion batteries.
基金financially supported by the Start-up Funding of Jinan University(No.88016105)the Discipline Construction Outstanding Young Backbone Project(No.12819023)+3 种基金the Fundamental Research Funds for the Central Universities(No.21620317)the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515110611 and 2021A1515010362)the Guangzhou Basic and Applied Basic Research Foundation(No.202102020995)supported by the Open Fund of Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications(No.2020B121201005)。
文摘Due to the abundant sodium reserves and high safety,sodium ion batteries(SIBs)are foreseen a promising future.While,hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages.However,the unsatisfactory initial coulombic efficiency(ICE)is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application.Herein,with spherical nano SiO_(2)as pore-forming agent,gelatin and polytetrafluoroethylene as carbon sources,a multi-porous carbon(MPC)material can be easily obtained via a co-pyrolysis method,by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases.As a result,the MPC anode exhibited remarkable ICE of 83%and a high rate capability(208 m Ah/g at 5 A/g)when used in sodium-ion half cells.Additionally,coupling with Na3V2(PO4)3as the cathode to assemble full cells,the as-fabricated MPC//NVP full cell delivered a good rate capability(146 m Ah/g at 5 A/g)as well,implying a good application prospect the MPC anode has.
基金supported by the National Natural Science Foundation of China(21905306,21975289,U19A2019)Hunan Province Natural Science Foundation(2020JJ5694)+1 种基金Hunan Provincial Science and Technology Plan Project of China(2017TP1001,2020JJ2042)Fundamental Research Funds for the Central South University(2020zzts060).
文摘Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great efforts have been devoted to developing high-performance carbonaceous materials with high capacity,long life span,and excellent rate capability,the low initial Coulombic efficiency(ICE)of high-capacity carbonaceous materials seriously limits their practical applications.Various methods have been successfully exploited,and a revolutionary impact has been achieved through the utilization of different techniques.Different carbonaceous materials possess different ion storage mechanisms,which means that the initial capacity loss may vary.However,there has rarely been a special review about the origins of and progress in the ICE for carbonaceous materials from the angle of the crystal structure.Hence,in this review,the structural differences between and ion storage mechanisms of various carbonaceous materials are first introduced.Then,we deduce the correlative factors of low ICE and thereafter summarize the proposed strategies to address these issues.Finally,some challenges,perspectives,and future directions on the ICE of carbonaceous materials are given.This review will provide deep insights into the challenges of improving the ICE of carbonaceous anodes for high-energy Li/Na-ion batteries,which will greatly contribute to their commercialization process.
基金support by the National Natural Science Foundation of China(Nos.21701163,21831006,21975244,21521001,and 22075268)the Natural Science Foundation of Anhui Provincial(No.1808085QB25)。
文摘The low initial Coulombic efficiency(ICE)of SiOx anode caused by the irreversible generation of LiySiOz and Li20 during lithiation process limits its application for high energy-density lithium-ion batteries.Herein,we report a molten-salt-induced thermochemical.prelithiation strategy for regulating the electrochemically active Si/O ratio of SiOx and thus enhancing ICE through thermal treatment of pre-synthesized LiNH2-coated SiOx in molten LiCl at 700℃.Bulk SiOx micro-particle was transformed into pomegranatelike prelithiated micro-cluster composite(M-Li-SiOx)with SiOx core and outer nano-sized agglomerates consisting of Li2Si20s,SiO2,and Si.Through the analysis of the reaction intermediates,molten-UC!could initiate reactions and promote mass transfer by the continuous extraction of oxygen component from SiOx particle inner in the form of inert Li2Si20s and SiO2 nanotubes to realize the.prelithiation.The degree of prelithiation can be regulated by adjusting the coating amount of LiNH2 layer,and the resulted M-Li-SiOx displays a prominent improvement of ICE from 58.73%to 88.2%.The graphite/M-Li-SiOx(8:2)composite electrode delivers a.discharge capacity of 497.29 mAh·g^(-1) with an ICE of 91.79%.By pairing graphite/M-Li-SiOx anode and LiFeP04 cathode in a full-cell an enhancement of energy density of 37.25%is realized compared with the full-cell containing graphite/SiOx anode.Furthermore,,ex-situ X-ray photoelectron spectroscopy(XPS)/Raman/X-ray diffraction(XRD)and related electrochemical measurements reveal the SiOx core and Si of M-Li-SiOx participate in the lithiation,and pre-generated Li2Si20s with u+diffusivity and pomegranate-like.structure reduces the reaction resistance and interface impedance of the solid electrolyte interphase(SEI)film.
基金the National Natural Science Foundation of China(Nos.21975026 and 22005033)Beijing Institute of Technology Research Fund Program for Young Scholars(No.XSQD-202108005)。
文摘Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of HC.In this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.
基金financially supported by National Key Research and Development Program of China (No.2019YFC1907805)National Natural Science Foundation of China (No.52004338)+1 种基金Hunan Provincial Natural Science Foundation of China (No.2020JJ5696)Guangdong Provincial Department of Natural Resources (No.2020-011)。
文摘Sodium-ion batteries(SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+ions consumption during the first cycle of charge/discharge process(due to the formation of the solid electrolyte interface(SEI) on the electrode surface and other irreversible reactions) is the factor that determines high performance SIBs and largely reduces the capacity of the full cell SIBs. Thus, the initial coulombic efficiency(ICE) of SIBs for both anode and cathode materials, is a key parameter for high performance SIBs, and the point is to increase the transport rate of the Na+ions. Therefore, developing SIBs with high ICE and rate performance becomes vital to boost the commercialization of SIBs. Here we provide a review on the methods to improve the ICE and the rate performance, by summarizing some methods of improving the ICE and rate performance of the anode and cathode materials for SIBs, and end by a conclusion with some perspectives and recommendations.
基金The authors acknowledge the support by Taihu Electric Corpo-ration 0001,the National Natural Science Foundation of China(51901206)the Fundamental Research Funds for the Central Uni-versities(2021QNA4003).
文摘All-solid-state lithium batteries(ASSLBs)employ high-capacity lithium(Li)metal as the anode and exhibit a higher energy density than that of conventional Li-ion batteries.However,the problems arose from the Li dendrites induce severely parasitic reaction between Li and electrolytes,leading to low coulombic efficiency(CE)and poor cyclic stability.Herein,a poly(vinylidene-co-hexafluoropropylene)/lithium nitrate(PVDF-HFP/LiNO_(3),marked as PFH/LN)artificial layer is employed to modified Li and achieve high CE ASSLBs with polyethylene oxide-Li_(6.4) La_(3)Zr_(1.4)Ta_(0.6)O_(12)(PEO-LLZTO)electrolyte.LN serves as a functionalized additive to facilitate the formation of a robust solid electrolyte interface(SEI),effi-ciently suppressing the formation of Li dendrites.Additionally,LN as a“binder”effectively links PFH with Li,providing good contact.PFH possesses high mechanical strength and moderate flexibility,which can not only physically inhibit the growth of Li dendrites,but also maintain the structural integrity of arti-ficial layer over long-term cycles.Finally,Li/Li cells with such artificial layer demonstrate ultralong cycle life of 1800 and 1000 h under 0.2 and 0.4 mA cm^(-1),respectively.Furtherly,high CE can be achieved when applied in both LiFePO 4 full cells and Li-Cu half cells.This work offers a facile and efficient strategy to greatly promote CE in PEO-based ASSLBs.
基金the National Natural Science Foundation of China and the Israeli Science Foundation for funding this research within the framework of the joint NSFC-ISF grant#51961145302supported by China Postdoctoral Science Foundation funded project(Grant#2020M682403).
文摘Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces,thus significantly degrading the cycling lifespan and decreasing the specific capacity.Here,we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl)borate(TFEB),based on 3,3,3-fluoroethylmethylcarbonate(FEMC)and fluoroethylene carbonate(FEC),which enables stable cycling of high nickel cathode(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),NMC811)under a cut-off voltage of 4.7 V in Li metal batteries.The electrolyte not only shows the fire-extinguishing properties,but also inhibits the transition metal dissolution,the gas production,side reactions on the cathode side.Therefore,the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode,delivering a specific capacity>220 mA h g^(-1),an average Coulombic efficiency>99.6%and capacity retention>99.7%over 100 cycles.
基金the financial support from the National Nature Science Foundation of China(No.U20A20249)the National Key Research and Development Program of China(2021YFB3800300)the Shenzhen Science and Technology Innovation Commission(KCXST20221021111216037)。
文摘Sodium-ion batteries(SIBs)are expected to offer affordability and high energy density for large-scale energy storage system.However,the commercial application of SIBs is hurdled by low initial coulombic efficiency(ICE),continuous Na loss during long-term operation,and low sodium-content of cathode materials.In this scenario,presodiation strategy by introducing an external sodium reservoir has been rationally proposed,which could supplement additional sodium ions into the system and thereby markedly improve both the cycling performance and energy density of SIBs.In this review,the significance of presodiation is initially introduced,followed by comprehensive interpretation on technological properties,underlying principles,and associated approaches,as well as our perspectives on present inferiorities and future research directions.Overall,this contribution outlines a distinct pathway towards the presodiation methodology,of significance but still in its nascent phase,which may inspire the targeted guidelines to explore new chemistry in this field.
基金This work was supported by Guangdong Basic and Applied Basic Research Foundation(2019A1515110530,2022A1515010486)Shenzhen Science and Technology Program(JCYJ20210324140804013)Tsinghua Shenzhen International Graduate School(QD2021005N,JC2021007).
文摘Green energy storage devices play vital roles in reducing fossil fuel emissions and achieving carbon neutrality by 2050.Growing markets for portable electronics and electric vehicles create tremendous demand for advanced lithium-ion batteries(LIBs)with high power and energy density,and novel electrode material with high capacity and energy density is one of the keys to next-generation LIBs.Silicon-based materials,with high specific capacity,abundant natural resources,high-level safety and environmental friendliness,are quite promising alternative anode materials.However,significant volume expansion and redundant side reactions with electrolytes lead to active lithium loss and decreased coulombic efficiency(CE)of silicon-based material,which hinders the commercial application of silicon-based anode.Prelithiation,preembedding extra lithium ions in the electrodes,is a promising approach to replenish the lithium loss during cycling.Recent progress on prelithiation strategies for silicon-based anode,including electrochemical method,chemical method,direct contact method,and active material method,and their practical potentials are reviewed and prospected here.The development of advanced Si-based material and prelithiation technologies is expected to provide promising approaches for the large-scale application of silicon-based materials.
