Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sampl...Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sample is well-crystallized and has a phase-pure a-NaFeO2 structure. The particle sizes are uniform, and distributed in the range of 20-200 nm. The initial discharge capacity of the Li/LiCo1/3Ni1/3Mn1/3O2 cell was about 149 mAh·g-1 when it was cycled at a voltage range of 4.5-2.3 V with a specific current of 0.25 mA. The result is better in comparison with solid-state solution method. The synthetic procedure was discussed. Three major reactions: chelation, esterification, and polymerization successively occurred.展开更多
Thermally grown oxides(TGOs)at the ceramic top-coat/metallic bond-coat interface are a pressing chal-lenge in advanced thermal barrier coating(TBC)systems as they can affect the performance and ser-vice lifetime of TB...Thermally grown oxides(TGOs)at the ceramic top-coat/metallic bond-coat interface are a pressing chal-lenge in advanced thermal barrier coating(TBC)systems as they can affect the performance and ser-vice lifetime of TBCs.Thus,developing novel TBC materials with ultralow oxygen ion diffusivity is very urgent.In this study,we reported the diffusive properties of oxygen ions in a novel pyrochlore-type La_(2)(Zr_(0.7)Ce_(0.3))_(2)O_(7)(LZ7C3)material.The measured ionic conductivity and atomistic simulation revealed that the oxygen ion diffusivity in LZ7C3 grains is two orders of magnitude lower than that in conventional 8 wt.%yttria-stabilized zirconia(8YSZ)grains.This is due to the relatively high energy barrier for oxygen hopping in LZ7C3.In addition,it was found that enhancing the order distribution of cations is a strategy to reduce the intrinsic oxygen diffusion of pyrochlore-type oxides.On the other hand,we observed that La^(3+) cations segregate at the grain boundaries(GBs)of LZ7C3,which results in the electrostatic poten-tial at GBs being comparable to that in the bulk.Furthermore,we found that the oxygen ion diffusion is facilitated at the GBs of LZ7C3 due to the stretched O-Zr/Ce bond and the low coordination at GBs.How-ever,the segregations of Y^(3+)cations and the increase in the number of oxygen vacancies resulted in the formation of an electrostatic layer at the GBs of 8YSZ,which shielded the oxygen ion diffusion.Despite this,the oxygen ion diffusivity in LZ7C3 was still considerably less than that in conventional 8YSZ.This study offers a stepping stone toward utilizing pyrochlore-type LZ7C3 materials as advanced TBCs at high temperatures.展开更多
P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale ...P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.展开更多
A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plate...A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plateau at ～4.2 V in the initial charge profile, indicating anionic redox reaction(ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ～210 mAh/g, which is probably derived from the participation of both ARR and Mn/Mnredox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mnhelps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.展开更多
The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered ma...The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2)) and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals (AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba)) were prepared by mesoporous template (P123)-assisted colloidal crystal template (CCT) and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%) values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.展开更多
The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis SEM, BET, TG/DTA and XRD in this paper. The results re- vealed that lithium and transition metal ions were trapp...The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis SEM, BET, TG/DTA and XRD in this paper. The results re- vealed that lithium and transition metal ions were trapped homogeneously on an atomic scale throughout the precursor Li2CO3, NiO and CoO are the intermediate products ob- tained after decomposition of the precursor and Li2CO3 un- dergoes direct reactions with NiO and CoO to form LiCo0.3Ni0.7O2. Moreover, the kinetics of formation of LiCo0.3Ni0.7O2 by citrate sol-gel method is faster than the case of the conventional solid-state reaction between lithium car- bonate and corresponding reactants. The single phase of LiCo0.3Ni0.7O2 was synthesized at temperature as low as 550℃. The discharge capacity of LiCo0.3Ni0.7O2 increases from 127 to 185 mAh/g as the calcination temperature in- creasing from 550 to 750℃. After 100 cycles, the discharge capacity of the sample calcined at 750℃ is 155 mAh/g. The electrochemical study shows that the LiCo0.3Ni0.7O2 has high discharge capacity and good cycling behavior for lithium ion batteries.展开更多
Due to its high operational voltage and energy density,P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) has become a leading cathode material for sodium-ion batteries(SIBs),which is an ideal option for large-scale energy storag...Due to its high operational voltage and energy density,P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) has become a leading cathode material for sodium-ion batteries(SIBs),which is an ideal option for large-scale energy storage.However,the practical application of P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) is limited by the capacity constraints and unwanted phase transitions,presenting significant challenges to the widespread application of SIBs.To address these challenges and optimize the electrochemical properties of the P2 phase cathode material,this study proposes a Cu and Zn co-doped strategy to improve the electrochemical performance.The incorporation of Cu/Zn can stabilize the P2-phase structure against P2-O2 phase transitions,thus enhancing its electrochemical properties.The as-obtained P2-type Na0.67[Ni_(0.3)Mn_(0.58)Cu_(0.09)Zn_(0.03)]O_(2) cathode material shows an impressive cycling stability,maintaining 80%capacity retention after 1000 cycles at 2 C.The cyclic voltammetry(CV)tests show that the Cu^(2+)/Cu^(3+)redox reaction is also involved in charge compensation during the charge/discharge process.展开更多
The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the wea...The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the weaker pollution and fewer profits of LiMn_(2)O_(4) cathode dispel the enthusiasm and responsibility of industry companies.Thus,a simplified and efncient method to regenerate the sodium-ion cathode materials and separate Li from spent LiMn_(2)O_(4) materials for the profit improvement is proposed.In detail,adjusting the parameters of carbothermal reduction process appropriately,the LiMn_(2)O_(4) spinel structure is destroyed within a short period time and transformed into simple metal oxide.As anticipated,nearly 95 wt.%lithium can be obtained and recovered during the water leaching,while 99 wt.%of manganese can be extracted in acid solution.Noted that the leaching residue can return to the carbothermic reduction,leading to a closed-loop economic recycling process.The regenerated Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) cathode displays excellent electrochemical performance with superior cycling stability(the initial capacity reaches 95.9 mAh·g^(-1),and the retention rate reached 98.3%after 100 cycles at 1 C).The delicate strategy of sodium-ion cathode material regenerated from spent LiMn_(2)O_(4) aims to realize lithium separation and material utilization of manganese simultaneously,providing the instructive suggestion to rise up the recycling profits of spent batteries.展开更多
A new medium entropy material LiCo_(0.25)Fe_(0.25)Mn_(0.2)5Ni_(0.2)5O_(2)(LCFMN)is proposed as a cathode for proton-conducting solid oxide fuel cells(H-SOFCs).Unlike traditional LiXO_(2)(X=Co,Fe,Mn,Ni)lithiated oxides...A new medium entropy material LiCo_(0.25)Fe_(0.25)Mn_(0.2)5Ni_(0.2)5O_(2)(LCFMN)is proposed as a cathode for proton-conducting solid oxide fuel cells(H-SOFCs).Unlike traditional LiXO_(2)(X=Co,Fe,Mn,Ni)lithiated oxides,which have issues like phase impurity,poor chemical compatibility,or poor fuel cell performance,the new LCFMN material mitigates these problems,allowing for the successful preparation of pure phase LCFMN with good chemical and thermal compatibility to the electrolyte.Furthermore,the entropy engineering strategy is found to weaken the covalence bond between the metal and oxygen in the LCFMN lattice,favoring the creation of oxygen vacancies and increasing cathode activity.As a result,the H-SOFC with the LCFMN cathode achieves an unprecedented fuel cell output of 1803 mW·cm^(−2)at 700℃,the highest ever reported for H-SOFCs with lithiated oxide cathodes.In addition to high fuel cell performance,the LCFMN cathode permits stable fuel cell operation for more than 450 h without visible degradation,demonstrating that LCFMN is a suitable cathode choice for H-SOFCs that combining high performance and good stability.展开更多
文摘Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sample is well-crystallized and has a phase-pure a-NaFeO2 structure. The particle sizes are uniform, and distributed in the range of 20-200 nm. The initial discharge capacity of the Li/LiCo1/3Ni1/3Mn1/3O2 cell was about 149 mAh·g-1 when it was cycled at a voltage range of 4.5-2.3 V with a specific current of 0.25 mA. The result is better in comparison with solid-state solution method. The synthetic procedure was discussed. Three major reactions: chelation, esterification, and polymerization successively occurred.
基金supported by the National Natural Science Foundation of China(Nos.11774280 and 11947136)Fundamental Research Funds for the Central Universities(No.xzy022019004)Natural Science Foundation of the Shaanxi Province(No.2020JQ339)。
文摘Thermally grown oxides(TGOs)at the ceramic top-coat/metallic bond-coat interface are a pressing chal-lenge in advanced thermal barrier coating(TBC)systems as they can affect the performance and ser-vice lifetime of TBCs.Thus,developing novel TBC materials with ultralow oxygen ion diffusivity is very urgent.In this study,we reported the diffusive properties of oxygen ions in a novel pyrochlore-type La_(2)(Zr_(0.7)Ce_(0.3))_(2)O_(7)(LZ7C3)material.The measured ionic conductivity and atomistic simulation revealed that the oxygen ion diffusivity in LZ7C3 grains is two orders of magnitude lower than that in conventional 8 wt.%yttria-stabilized zirconia(8YSZ)grains.This is due to the relatively high energy barrier for oxygen hopping in LZ7C3.In addition,it was found that enhancing the order distribution of cations is a strategy to reduce the intrinsic oxygen diffusion of pyrochlore-type oxides.On the other hand,we observed that La^(3+) cations segregate at the grain boundaries(GBs)of LZ7C3,which results in the electrostatic poten-tial at GBs being comparable to that in the bulk.Furthermore,we found that the oxygen ion diffusion is facilitated at the GBs of LZ7C3 due to the stretched O-Zr/Ce bond and the low coordination at GBs.How-ever,the segregations of Y^(3+)cations and the increase in the number of oxygen vacancies resulted in the formation of an electrostatic layer at the GBs of 8YSZ,which shielded the oxygen ion diffusion.Despite this,the oxygen ion diffusivity in LZ7C3 was still considerably less than that in conventional 8YSZ.This study offers a stepping stone toward utilizing pyrochlore-type LZ7C3 materials as advanced TBCs at high temperatures.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12105372 and 51991344)President's Foundation of China Institute of Atomic Energy(Grant No.16YZ202212000201)Chinese Academy of Sciences(Grant No.XDB33000000).
文摘P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.
基金supported by funding from Science and Technology Project of the State Grid Corporation of China("research on key technology of low-strain layered oxides for long-life Na-ion batteries",No.DG71-16-027)
文摘A new model material of Na[Mg(Ⅱ)Mn(Ⅳ)]O, with only Mgand Mnin the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ～130 mAh/g with a long plateau at ～4.2 V in the initial charge profile, indicating anionic redox reaction(ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ～210 mAh/g, which is probably derived from the participation of both ARR and Mn/Mnredox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mnhelps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.
基金supported by Key Research and Development Program of Ministry of Science and Technology of the People’s Republic of China (MOST) (No. 2017YFE0131200) for collaboration between China and PolandNational Nature Science Foundation of China (NSFC) (Nos. 22072095, U1908204, 21761162016)+3 种基金General Projects of Liaoning Province Natural Fund (No. 2019-MS-284)National Engineering Laboratory for Mobile Source Emission Control Technology (No. NELMS2018A04)University level innovation team of Shenyang Normal University, Major Incubation Program of Shenyang Normal University (No. ZD201901)supported by the Research Grants Council (RGC) of Hong Kong through NSFC/RGC Joint Research Scheme (No. N_CUHK451/17)。
文摘The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2)) and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals (AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba)) were prepared by mesoporous template (P123)-assisted colloidal crystal template (CCT) and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%) values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.
基金the EH.D Foundation of China(Grant No.20020610027)
文摘The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis SEM, BET, TG/DTA and XRD in this paper. The results re- vealed that lithium and transition metal ions were trapped homogeneously on an atomic scale throughout the precursor Li2CO3, NiO and CoO are the intermediate products ob- tained after decomposition of the precursor and Li2CO3 un- dergoes direct reactions with NiO and CoO to form LiCo0.3Ni0.7O2. Moreover, the kinetics of formation of LiCo0.3Ni0.7O2 by citrate sol-gel method is faster than the case of the conventional solid-state reaction between lithium car- bonate and corresponding reactants. The single phase of LiCo0.3Ni0.7O2 was synthesized at temperature as low as 550℃. The discharge capacity of LiCo0.3Ni0.7O2 increases from 127 to 185 mAh/g as the calcination temperature in- creasing from 550 to 750℃. After 100 cycles, the discharge capacity of the sample calcined at 750℃ is 155 mAh/g. The electrochemical study shows that the LiCo0.3Ni0.7O2 has high discharge capacity and good cycling behavior for lithium ion batteries.
基金supported by the National Natural Science Foundation of China(Nos.22179077,51774251,21908142)Shanghai Science and Technology Commission’s“2020 Science and Technology In-novation Action Plan”(No.20511104003)Natural Science Foundation in Shanghai(No.21ZR1424200)。
文摘Due to its high operational voltage and energy density,P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) has become a leading cathode material for sodium-ion batteries(SIBs),which is an ideal option for large-scale energy storage.However,the practical application of P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) is limited by the capacity constraints and unwanted phase transitions,presenting significant challenges to the widespread application of SIBs.To address these challenges and optimize the electrochemical properties of the P2 phase cathode material,this study proposes a Cu and Zn co-doped strategy to improve the electrochemical performance.The incorporation of Cu/Zn can stabilize the P2-phase structure against P2-O2 phase transitions,thus enhancing its electrochemical properties.The as-obtained P2-type Na0.67[Ni_(0.3)Mn_(0.58)Cu_(0.09)Zn_(0.03)]O_(2) cathode material shows an impressive cycling stability,maintaining 80%capacity retention after 1000 cycles at 2 C.The cyclic voltammetry(CV)tests show that the Cu^(2+)/Cu^(3+)redox reaction is also involved in charge compensation during the charge/discharge process.
基金supported by the National Natural Science Foundation of China(52070194,52073309)the Natural Science Foundation of Hunan Province(2022JJ20069)。
文摘The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the weaker pollution and fewer profits of LiMn_(2)O_(4) cathode dispel the enthusiasm and responsibility of industry companies.Thus,a simplified and efncient method to regenerate the sodium-ion cathode materials and separate Li from spent LiMn_(2)O_(4) materials for the profit improvement is proposed.In detail,adjusting the parameters of carbothermal reduction process appropriately,the LiMn_(2)O_(4) spinel structure is destroyed within a short period time and transformed into simple metal oxide.As anticipated,nearly 95 wt.%lithium can be obtained and recovered during the water leaching,while 99 wt.%of manganese can be extracted in acid solution.Noted that the leaching residue can return to the carbothermic reduction,leading to a closed-loop economic recycling process.The regenerated Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) cathode displays excellent electrochemical performance with superior cycling stability(the initial capacity reaches 95.9 mAh·g^(-1),and the retention rate reached 98.3%after 100 cycles at 1 C).The delicate strategy of sodium-ion cathode material regenerated from spent LiMn_(2)O_(4) aims to realize lithium separation and material utilization of manganese simultaneously,providing the instructive suggestion to rise up the recycling profits of spent batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272216 and 51972183)the Hundred Youth Talents Program of Hunan,and the Startup Funding for Talents at University of South China.
文摘A new medium entropy material LiCo_(0.25)Fe_(0.25)Mn_(0.2)5Ni_(0.2)5O_(2)(LCFMN)is proposed as a cathode for proton-conducting solid oxide fuel cells(H-SOFCs).Unlike traditional LiXO_(2)(X=Co,Fe,Mn,Ni)lithiated oxides,which have issues like phase impurity,poor chemical compatibility,or poor fuel cell performance,the new LCFMN material mitigates these problems,allowing for the successful preparation of pure phase LCFMN with good chemical and thermal compatibility to the electrolyte.Furthermore,the entropy engineering strategy is found to weaken the covalence bond between the metal and oxygen in the LCFMN lattice,favoring the creation of oxygen vacancies and increasing cathode activity.As a result,the H-SOFC with the LCFMN cathode achieves an unprecedented fuel cell output of 1803 mW·cm^(−2)at 700℃,the highest ever reported for H-SOFCs with lithiated oxide cathodes.In addition to high fuel cell performance,the LCFMN cathode permits stable fuel cell operation for more than 450 h without visible degradation,demonstrating that LCFMN is a suitable cathode choice for H-SOFCs that combining high performance and good stability.
