The widespread applications of lithium-ion batteries(LIBs)generate tons of spent LIBs.Therefore,recycling LIBs is of paramount importance in protecting the environment and saving the resources.Current commercialized L...The widespread applications of lithium-ion batteries(LIBs)generate tons of spent LIBs.Therefore,recycling LIBs is of paramount importance in protecting the environment and saving the resources.Current commercialized LIBs mostly adopt layered oxides such as LiCoO_(2)(LCO)or LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NMC)as the cathode materials.Converting the intercalation-type spent oxides into conversion-type cathodes(such as metal fluorides(MFs))offers a valid recycling strategy and provides substantially improved energy densities for LIBs.Herein,two typical Co-based cathodes,LCO and LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NMC622),in spent LIBs were successfully converted to CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) cathodes by a reduction and fluorination technique.The as converted CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) delivered cell energy densities of 650 and 700 Wh/kg,respectively.Advanced atomic-level electron microscopy revealed that the used LCO and NMC622 were converted to highly phase pure Co metal and Ni_(0.6)Co_(0.2)Mn_(0.2) alloys in the used graphite-assisted reduction roasting,simultaneously producing the important product of Li_(2)CO_(3) using only environment friendly solvent.Our study provided a versatile strategy to convert the intercalation-type Co-based cathode in the spent LIBs into conversion-type MFs cathodes,which offers a new avenue to recycle the spent LIBs and substantially increase the energy densities of next generation LIBs.展开更多
Copper sulfide(CuS)is a promising cathode for lithium-ion batteries(LIBs)due to its impeccable theoretical energy density(~1015 Wh·kg^(−1) and 4743 Wh·L^(−1)).However,it suffers from voltage decay leaded ene...Copper sulfide(CuS)is a promising cathode for lithium-ion batteries(LIBs)due to its impeccable theoretical energy density(~1015 Wh·kg^(−1) and 4743 Wh·L^(−1)).However,it suffers from voltage decay leaded energy density loss and low energy efficiency,which hinders its application.In this work,with combined ex-situ/in-situ X-ray diffraction(XRD)and electrochemical analysis,we explore detailed degradation mechanisms.For the voltage decay,it is attributed to a spontaneous reaction between CuS cathode and copper current collector(Cu CC).This reaction leads to energy density loss and active materials degradation(CuS→Cu_(1.81)S).As for energy efficiency,CuS undergoes a series of phase transformations.The main phase transition processes are CuS→α-LiCuS→Li_(2−x)Cu_(x)S+Cu→Li_(2)S+Cu for discharge;Li_(2)S+Cu→Li_(2−x)Cu_(x)S→β-LiCuS→CuS for charge.Here,α-LiCuS,β-LiCuS,and Li_(2−x)CuxS are newly identified phases.These phase changes are driven by topotactic-reaction-related copper diffusion and rearrangement.This work demonstrates the significance of transition-metal diffusion in the intermediates formation and phase change in conversion-type materials.展开更多
Potassium-ion batteries(KIBs)have become the most promising alternative to lithium-ion batteries for large-scale energy storage system due to their abundance and low cost.However,previous reports focused on the interc...Potassium-ion batteries(KIBs)have become the most promising alternative to lithium-ion batteries for large-scale energy storage system due to their abundance and low cost.However,previous reports focused on the intercalation-type cathode materials usually showed an inferior capacity,together with a poor cyclic life caused by the repetitive intercalation of large-size K-ions,which hinders their practical application.Here,we combine the strategies of carbon coating,template etching and hydrothermal selenization to prepare yolk-shelled FeSe_(2)@N-doped carbon nanoboxes(FeSe_(2)@C NBs),where the inner highly-crystalline FeSe_(2)clusters are completely surrounded by the self-supported carbon shell.The integrated and highly conductive carbon shell not only provides a fast electron/ion diffusion channel,but also prevents the agglomeration of FeSe_(2)clusters.When evaluated as a conversion-type cathode material for KIBs,the FeSe_(2)@C NBs electrode delivers a relatively high specific capacity of 257 mAh/g at 100 mA/g and potential platform of about 1.6 V,which endow a high energy density of about 411 Wh/kg.Most importantly,by designing a robust host with large internal void space to accommodate the volumetric variation of the inner FeSe_(2)clusters,the battery based on FeSe_(2)@C NBs exhibits ultra-long cycle stability.Specifically,even after 700 cycles at 100 mA/g,a capacity of 221 mAh/g along with an average fading rate of only 0.02%can be retained,which achieves the optimal balance of high specific capacity and long-cycle stability.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U20A20336,21935009,52002346,52022088,51971245,22205191)the Science and Technology Innovation Program of Hunan Province(No.2021RC3109)+1 种基金the Natural Science Foundation of Hunan Province,China(No.2022JJ40446)Natural Science Foundation of Hebei Province(Nos.B2020203037,B2018203297).
文摘The widespread applications of lithium-ion batteries(LIBs)generate tons of spent LIBs.Therefore,recycling LIBs is of paramount importance in protecting the environment and saving the resources.Current commercialized LIBs mostly adopt layered oxides such as LiCoO_(2)(LCO)or LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NMC)as the cathode materials.Converting the intercalation-type spent oxides into conversion-type cathodes(such as metal fluorides(MFs))offers a valid recycling strategy and provides substantially improved energy densities for LIBs.Herein,two typical Co-based cathodes,LCO and LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NMC622),in spent LIBs were successfully converted to CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) cathodes by a reduction and fluorination technique.The as converted CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) delivered cell energy densities of 650 and 700 Wh/kg,respectively.Advanced atomic-level electron microscopy revealed that the used LCO and NMC622 were converted to highly phase pure Co metal and Ni_(0.6)Co_(0.2)Mn_(0.2) alloys in the used graphite-assisted reduction roasting,simultaneously producing the important product of Li_(2)CO_(3) using only environment friendly solvent.Our study provided a versatile strategy to convert the intercalation-type Co-based cathode in the spent LIBs into conversion-type MFs cathodes,which offers a new avenue to recycle the spent LIBs and substantially increase the energy densities of next generation LIBs.
基金supported by the National Natural Science Foundation of China(No.52072061)the Natural Science Foundation of Sichuan,China(No.2023NSFSC1914).
文摘Copper sulfide(CuS)is a promising cathode for lithium-ion batteries(LIBs)due to its impeccable theoretical energy density(~1015 Wh·kg^(−1) and 4743 Wh·L^(−1)).However,it suffers from voltage decay leaded energy density loss and low energy efficiency,which hinders its application.In this work,with combined ex-situ/in-situ X-ray diffraction(XRD)and electrochemical analysis,we explore detailed degradation mechanisms.For the voltage decay,it is attributed to a spontaneous reaction between CuS cathode and copper current collector(Cu CC).This reaction leads to energy density loss and active materials degradation(CuS→Cu_(1.81)S).As for energy efficiency,CuS undergoes a series of phase transformations.The main phase transition processes are CuS→α-LiCuS→Li_(2−x)Cu_(x)S+Cu→Li_(2)S+Cu for discharge;Li_(2)S+Cu→Li_(2−x)Cu_(x)S→β-LiCuS→CuS for charge.Here,α-LiCuS,β-LiCuS,and Li_(2−x)CuxS are newly identified phases.These phase changes are driven by topotactic-reaction-related copper diffusion and rearrangement.This work demonstrates the significance of transition-metal diffusion in the intermediates formation and phase change in conversion-type materials.
基金the financial support from the National Postdoctoral Program for Innovation Talents(No.BX201700103)China Postdoctoral Science Foundation Funded Project(No.2018M633664).
文摘Potassium-ion batteries(KIBs)have become the most promising alternative to lithium-ion batteries for large-scale energy storage system due to their abundance and low cost.However,previous reports focused on the intercalation-type cathode materials usually showed an inferior capacity,together with a poor cyclic life caused by the repetitive intercalation of large-size K-ions,which hinders their practical application.Here,we combine the strategies of carbon coating,template etching and hydrothermal selenization to prepare yolk-shelled FeSe_(2)@N-doped carbon nanoboxes(FeSe_(2)@C NBs),where the inner highly-crystalline FeSe_(2)clusters are completely surrounded by the self-supported carbon shell.The integrated and highly conductive carbon shell not only provides a fast electron/ion diffusion channel,but also prevents the agglomeration of FeSe_(2)clusters.When evaluated as a conversion-type cathode material for KIBs,the FeSe_(2)@C NBs electrode delivers a relatively high specific capacity of 257 mAh/g at 100 mA/g and potential platform of about 1.6 V,which endow a high energy density of about 411 Wh/kg.Most importantly,by designing a robust host with large internal void space to accommodate the volumetric variation of the inner FeSe_(2)clusters,the battery based on FeSe_(2)@C NBs exhibits ultra-long cycle stability.Specifically,even after 700 cycles at 100 mA/g,a capacity of 221 mAh/g along with an average fading rate of only 0.02%can be retained,which achieves the optimal balance of high specific capacity and long-cycle stability.
