The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming ag...The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming agents is not well understood.Herein,an effective chemical activation followed by a high-temperature self-healing strategy is employed to generate interconnected closed pores in lignin-derived hard carbon(HCs).By systematic experimental design combined with electron paramagnetic res-onance spectroscopy,it can be found that the content of free radicals in the carbon matrix influences the closure of open pores at high temperatures.Excessively high activation temperature(>700 C)leads to a low free radical concentration,making it difficult to achieve self-healing of open pores at high tempera-tures.By activation at 700°C,a balance between pore making and self-healing is achieved in the final hard carbon.A large number of free radicals triggers rapid growth and aggregation of carbon microcrys-tals,blocking pre-formed open micropores and creating additional interconnected closed pores in as-obtained hard carbons.As a result,the optimized carbon anode(LK-700-1300)delivers a high reversible capacity of 330.8 mA h g^(-1) at 0.03 A g^(-1),which is an increase of 86 mA h g^(-1) compared to the pristine lignin-derived carbon anode(L-700-1300),and exhibits a good rate performance(202.1 mA h g^(-1) at 1 A g^(-1)).This work provides a universal and effective guidance for tuning closed pores of hard carbons from otherprecursors.展开更多
N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to...N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to characterize.Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials.Thus,we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance,in-situ X-ray photoelectron spectroscopy,and time-offlight secondary ion mass spectrometry.We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane(IHP),which prevents ion rearrangement and enhances the migration of cations.However,this specific adsorption accelerated solvent decomposition,rendering rapid performance degradation in practical devices.This work reveals that the surface chemistry of electrodes can cause specific adsorption of solvents and change the EDL structure,which complements the classical EDL theory and provide guidance for practical applications.展开更多
Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. T...Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. The renewable biomass is a green and economically attractive carbon source to produce hard carbons. However, the chemical and structural complexity of biomass has plagued the understanding of evolution mechanism from organic precursors to hard carbons and the structure-property relationship.This makes it difficult to finely tune the microstructure of biomass-derived hard carbons, thus greatly restricting their high-performance applications. Most recently, the optimal utilization and controllable conversion of biomass-derived biopolymers(such as starch, cellulose and lignin) at the molecular level have become a burgeoning area of research to develop hard carbons for advanced batteries.Considering the principal source of carbonaceous materials is from biomass pyrolysis, we firstly overview the chemical structures and pyrolysis behaviors of three main biopolymers. Then, the controllable preparation of hard carbons using various physicochemical properties of biopolymers at the molecular level is systematically discussed. Furthermore, we highlight present challenges and further opportunities in this field. The Review will guide future research works on the design of sustainable hard carbons and the optimization of battery performance.展开更多
Redox-active organic electrode materials are highly desirable in realizing next-generation all-in-one bendable electronic systems.Herein,a novel flexible supercapacitors(SCs)electrode is fabricated from poly(anthraqui...Redox-active organic electrode materials are highly desirable in realizing next-generation all-in-one bendable electronic systems.Herein,a novel flexible supercapacitors(SCs)electrode is fabricated from poly(anthraquinonyl sulfide)(PAQS)and single-walled carbon nanotubes(SWCNTs)suspension by a simple vacuum filtration and named as PAQS-SWCNTs.The PAQS-SWCNTs electrode offered an initial capacitance of 223 F·g^-1 and outstanding capacitance retention up to 78.4%after 3×10^4 charge-discharge cycles at 0.5 A·g^-1 current density.In a high potential range(0-3 V)and aprotic electrolyte,the PAQS-SWCNTs electrodes in coin cell exhibited an outstanding energy density of 69 Wh·kg^-1 at a power density of 90.6 W·kg^-1,whereas in the fabricated flexible SCs it retained 63.2 Wh·kg^-1.The PAQS-SWCNTs electrodes also showed extraordinary performance at a higher current density(20 A·g^-1)and maintained a specific capacitance of 55 and 47 F·g^-1 for coin and flexible SCs,respectively.Moreover,the flexible SC is further verified to be able to illuminate up multiple LEDs.These futuristic findings showed that the SCs assembled with flexible PAQS-SWCNTs electrodes have potential application in energy-storage devices and make them highly appealing for future redox supercapacitors.展开更多
Transition metal chalcogenides(TMCs)and TMCs-based nanocomposites have attracted extensive attention due to their versatile material species,low cost,and rich physical and chemical characteristics.As anode materials o...Transition metal chalcogenides(TMCs)and TMCs-based nanocomposites have attracted extensive attention due to their versatile material species,low cost,and rich physical and chemical characteristics.As anode materials of lithium-ion capacitors(LICs),TMCs have exhibited high theoretical capacities and pseudocapacitance storage mechanism.However,there are many intrinsic challenges,such as low electrical conductivity,repeatedly high-volume changes and sluggish ionic diffusion kinetics.Hence,many traditional and unconventional techniques have been reported to solve these critical problems,and many innovative strategies are also used to prepare high quality anode materials for LICs.In this mini review,a detailed family member list and comparison of TMCs in the field of lithium-ion capacitors have been summarized firstly.Then,many rectification stratagems and recent researches of TMCs have been exhibited and discussed.In the end,as an outcome of these discussions,some further challenges and perspectives are envisioned to promote the application of TMCs materials for lithium-ion c apacitors.展开更多
Lithium-(Li-)ion batteries have revolutionized our daily life towards wireless and clean style,and the demand for batteries with higher energy density and better safety is highly required.The next-generation batteries...Lithium-(Li-)ion batteries have revolutionized our daily life towards wireless and clean style,and the demand for batteries with higher energy density and better safety is highly required.The next-generation batteries with innovatory chemistry,material,and engineering breakthroughs are in strong pursuit currently.Herein,the key historical developments of practical electrode materials in Li-ion batteries are summarized as the cornerstone for the innovation of next-generation batteries.In addition,the emerging electrode materials for next-generation batteries are discussed as the revolving challenges and potential strategies.Finally,the future scenario of high-energy-density rechargeable batteries is presented.The combination of theory and experiment under multiscale is highlighted to promote the development of emerging electrode materials.展开更多
基金supported by the National Natural Science Foundation of China (22379157,22179139)the Key Research and Development (R&D) Projects of Shanxi Province(202102040201003)+1 种基金the Research Program of Shanxi Province(202203021211203)the ICC CAS (SCJC-XCL-2023-10 and SCJC-XCL-2023-13)
文摘The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming agents is not well understood.Herein,an effective chemical activation followed by a high-temperature self-healing strategy is employed to generate interconnected closed pores in lignin-derived hard carbon(HCs).By systematic experimental design combined with electron paramagnetic res-onance spectroscopy,it can be found that the content of free radicals in the carbon matrix influences the closure of open pores at high temperatures.Excessively high activation temperature(>700 C)leads to a low free radical concentration,making it difficult to achieve self-healing of open pores at high tempera-tures.By activation at 700°C,a balance between pore making and self-healing is achieved in the final hard carbon.A large number of free radicals triggers rapid growth and aggregation of carbon microcrys-tals,blocking pre-formed open micropores and creating additional interconnected closed pores in as-obtained hard carbons.As a result,the optimized carbon anode(LK-700-1300)delivers a high reversible capacity of 330.8 mA h g^(-1) at 0.03 A g^(-1),which is an increase of 86 mA h g^(-1) compared to the pristine lignin-derived carbon anode(L-700-1300),and exhibits a good rate performance(202.1 mA h g^(-1) at 1 A g^(-1)).This work provides a universal and effective guidance for tuning closed pores of hard carbons from otherprecursors.
基金the National Science Foundation for Excellent Young Scholars of China(21922815)the National Natural Science Foundation of China(22179139)+2 种基金the National Key Research and Development Program of China(2020YFB1505800)the Youth Innovation Promotion Association of CAS(2019178)the“Transformational Technologies for Clean Energy and Demonstration”Strategic Priority Research Program of the CAS(XDA21000000)。
文摘N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to characterize.Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials.Thus,we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance,in-situ X-ray photoelectron spectroscopy,and time-offlight secondary ion mass spectrometry.We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane(IHP),which prevents ion rearrangement and enhances the migration of cations.However,this specific adsorption accelerated solvent decomposition,rendering rapid performance degradation in practical devices.This work reveals that the surface chemistry of electrodes can cause specific adsorption of solvents and change the EDL structure,which complements the classical EDL theory and provide guidance for practical applications.
基金the support of this work by the Fundamental Research Program of Shanxi Province(20210302123008,20210302124101)the Youth Innovation Promotion Association of CAS(2019178)+1 种基金the National Science Foundation for Excellent Young Scholars of China(21922815)the National Natural Science Foundation of China(21975275,22179139)。
文摘Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. The renewable biomass is a green and economically attractive carbon source to produce hard carbons. However, the chemical and structural complexity of biomass has plagued the understanding of evolution mechanism from organic precursors to hard carbons and the structure-property relationship.This makes it difficult to finely tune the microstructure of biomass-derived hard carbons, thus greatly restricting their high-performance applications. Most recently, the optimal utilization and controllable conversion of biomass-derived biopolymers(such as starch, cellulose and lignin) at the molecular level have become a burgeoning area of research to develop hard carbons for advanced batteries.Considering the principal source of carbonaceous materials is from biomass pyrolysis, we firstly overview the chemical structures and pyrolysis behaviors of three main biopolymers. Then, the controllable preparation of hard carbons using various physicochemical properties of biopolymers at the molecular level is systematically discussed. Furthermore, we highlight present challenges and further opportunities in this field. The Review will guide future research works on the design of sustainable hard carbons and the optimization of battery performance.
基金supported by the Ministry of Science and Technology of China(Nos.2016YFF0203803 and 2016YFA020070)the National Natural Science Foundation of China(Nos.51473039 and 21534003)+2 种基金Scientific and Technological Key Project of Shanxi Province(Nos.MC2016-04 and MC2016-08)Natural Science Foundations of Shanxi Province(No.201801D221156)DNL Cooperation Fund of CAS(No.DNL180308)the World Academy of Sciences under the CAS-TWAS PhD President's Fellowship Program.
文摘Redox-active organic electrode materials are highly desirable in realizing next-generation all-in-one bendable electronic systems.Herein,a novel flexible supercapacitors(SCs)electrode is fabricated from poly(anthraquinonyl sulfide)(PAQS)and single-walled carbon nanotubes(SWCNTs)suspension by a simple vacuum filtration and named as PAQS-SWCNTs.The PAQS-SWCNTs electrode offered an initial capacitance of 223 F·g^-1 and outstanding capacitance retention up to 78.4%after 3×10^4 charge-discharge cycles at 0.5 A·g^-1 current density.In a high potential range(0-3 V)and aprotic electrolyte,the PAQS-SWCNTs electrodes in coin cell exhibited an outstanding energy density of 69 Wh·kg^-1 at a power density of 90.6 W·kg^-1,whereas in the fabricated flexible SCs it retained 63.2 Wh·kg^-1.The PAQS-SWCNTs electrodes also showed extraordinary performance at a higher current density(20 A·g^-1)and maintained a specific capacitance of 55 and 47 F·g^-1 for coin and flexible SCs,respectively.Moreover,the flexible SC is further verified to be able to illuminate up multiple LEDs.These futuristic findings showed that the SCs assembled with flexible PAQS-SWCNTs electrodes have potential application in energy-storage devices and make them highly appealing for future redox supercapacitors.
基金financially supported by the National Natural Science Foundation of China(No.51907193)the Key Research Program of Frontier Sciences,CAS(No.ZDBS-LYJSC047)+1 种基金the Youth Innovation Promotion Association CAS(No.2020145)Dalian National Laboratory for Clean Energy Cooperation Fund,the CAS(No.DNL201915)。
文摘Transition metal chalcogenides(TMCs)and TMCs-based nanocomposites have attracted extensive attention due to their versatile material species,low cost,and rich physical and chemical characteristics.As anode materials of lithium-ion capacitors(LICs),TMCs have exhibited high theoretical capacities and pseudocapacitance storage mechanism.However,there are many intrinsic challenges,such as low electrical conductivity,repeatedly high-volume changes and sluggish ionic diffusion kinetics.Hence,many traditional and unconventional techniques have been reported to solve these critical problems,and many innovative strategies are also used to prepare high quality anode materials for LICs.In this mini review,a detailed family member list and comparison of TMCs in the field of lithium-ion capacitors have been summarized firstly.Then,many rectification stratagems and recent researches of TMCs have been exhibited and discussed.In the end,as an outcome of these discussions,some further challenges and perspectives are envisioned to promote the application of TMCs materials for lithium-ion c apacitors.
基金the National Natural Science Foundation of China(21776019,21825501,and U1801257)Energy Material Advances 11 the National Key Research and Development Program(2016YFA0202500)+3 种基金the Beijing Natural Science Foundation(L182021)the Foundation of National Key Laboratory(6142808190201)the Scientific and Technological Key Project of Shanxi Province(20191102003)the Tsinghua University Initiative Scientific Research Program.References。
文摘Lithium-(Li-)ion batteries have revolutionized our daily life towards wireless and clean style,and the demand for batteries with higher energy density and better safety is highly required.The next-generation batteries with innovatory chemistry,material,and engineering breakthroughs are in strong pursuit currently.Herein,the key historical developments of practical electrode materials in Li-ion batteries are summarized as the cornerstone for the innovation of next-generation batteries.In addition,the emerging electrode materials for next-generation batteries are discussed as the revolving challenges and potential strategies.Finally,the future scenario of high-energy-density rechargeable batteries is presented.The combination of theory and experiment under multiscale is highlighted to promote the development of emerging electrode materials.
