Solid-state lithium batteries may provide increased energy density and improved safety compared with Li-ion technology.However,in a solid-state composite cathode,mechanical degradation due to repeated cathode volume c...Solid-state lithium batteries may provide increased energy density and improved safety compared with Li-ion technology.However,in a solid-state composite cathode,mechanical degradation due to repeated cathode volume changes during cycling may occur,whichmay be partially mitigated by applying a significant,but often impractical,uniaxial stack pressure.Herein,we compare the behavior of composite electrodes based on Li4Ti5O12(LTO)(negligible volume change)and Nb2O5(+4%expansion)cycled at different stack pressures.The initial LTO capacity and retention are not affected by pressure but for Nb2O5,they are significantly lower when a stack pressure of<2MPa is applied,due to inter-particle cracking and solid-solid contact loss because of cyclic volume changes.Thiswork confirms the importance of cathode mechanical stability and the stack pressures for long-term cyclability for solid-state batteries.This suggests that low volumechange cathode materials or a proper buffer layer are required for solid-state batteries,especially at low stack pressures.展开更多
Intercalation transition metal oxides (ITMO)have attracted great attention as lithium-ion battery negative electrodes due to high operation safety,high capacity and rapid ion intercalation.However,the intrinsic low el...Intercalation transition metal oxides (ITMO)have attracted great attention as lithium-ion battery negative electrodes due to high operation safety,high capacity and rapid ion intercalation.However,the intrinsic low electron conductivity plagues the lifetime and cell performance of the ITMO negative electrode.Here we design a new carbon-emcoating architecture through single CO_(2)activation treatment as demonstrated by the Nb_(2)O_(5)/C nanohybrid.Triple structure engineering of the carbon-emcoating Nb_(2)O_(5)/C nanohybrid is achieved in terms of porosity,composition,and crystallographic phase.The carbon-embedding Nb_(2)O_(5)/C nanohybrids show superior cycling and rate performance compared with the conventional carbon coating,with reversible capacity of 387 m A h g(-1)at 0.2 C and 92%of capacity retained after 500cycles at 1 C.Differential electrochemical mass spectrometry(DEMS) indicates that the carbon emcoated Nb_(2)O_(5)nanohybrids present less gas evolution than commercial lithium titanate oxide during cycling.The unique carbon-emcoating technique can be universally applied to other ITMO negative electrodes to achieve high electrochemical performance.展开更多
基金Henry Royce Institute,Grant/Award Numbers:FIRG007,EP/R0066X/1,FIRG008Engineering and Physical Sciences Research Council,Grant/Award Number:EP/M009521/1National Natural Science Foundation of China,Grant/Award Number:22309110。
文摘Solid-state lithium batteries may provide increased energy density and improved safety compared with Li-ion technology.However,in a solid-state composite cathode,mechanical degradation due to repeated cathode volume changes during cycling may occur,whichmay be partially mitigated by applying a significant,but often impractical,uniaxial stack pressure.Herein,we compare the behavior of composite electrodes based on Li4Ti5O12(LTO)(negligible volume change)and Nb2O5(+4%expansion)cycled at different stack pressures.The initial LTO capacity and retention are not affected by pressure but for Nb2O5,they are significantly lower when a stack pressure of<2MPa is applied,due to inter-particle cracking and solid-solid contact loss because of cyclic volume changes.Thiswork confirms the importance of cathode mechanical stability and the stack pressures for long-term cyclability for solid-state batteries.This suggests that low volumechange cathode materials or a proper buffer layer are required for solid-state batteries,especially at low stack pressures.
基金supported by the National Key R&D Program of China(2016YFB0100100)the National Natural Science Foundation of China(51702335 and 21773279)+8 种基金Zhejiang Non-profit Technology Applied Research Program(LGG19B010001)Ningbo Municipal Natural Science Foundation(2018A610084)the CAS-EU S&T Cooperation Partner Program(174433KYSB20150013)the Key Laboratory of Bio-based Polymeric Materials of Zhejiang Provincethe funding from Marie Sklodowska-Curie Fellowship in EUthe Engineering and Physical Sciences Research Council(EPSRC),including the SUPERGEN Energy Storage Hub(EP/L019469/1)Enabling Next Generation Lithium Batteries(EP/M009521/1)Henry Royce Institute for Advanced Materials(EP/R00661X/1,EP/S019367/1,EP/R010145/1)the Faraday Institution All-Solid-State Batteries with Li and Na Anodes(FIRG007,FIRG008)for financial support。
文摘Intercalation transition metal oxides (ITMO)have attracted great attention as lithium-ion battery negative electrodes due to high operation safety,high capacity and rapid ion intercalation.However,the intrinsic low electron conductivity plagues the lifetime and cell performance of the ITMO negative electrode.Here we design a new carbon-emcoating architecture through single CO_(2)activation treatment as demonstrated by the Nb_(2)O_(5)/C nanohybrid.Triple structure engineering of the carbon-emcoating Nb_(2)O_(5)/C nanohybrid is achieved in terms of porosity,composition,and crystallographic phase.The carbon-embedding Nb_(2)O_(5)/C nanohybrids show superior cycling and rate performance compared with the conventional carbon coating,with reversible capacity of 387 m A h g(-1)at 0.2 C and 92%of capacity retained after 500cycles at 1 C.Differential electrochemical mass spectrometry(DEMS) indicates that the carbon emcoated Nb_(2)O_(5)nanohybrids present less gas evolution than commercial lithium titanate oxide during cycling.The unique carbon-emcoating technique can be universally applied to other ITMO negative electrodes to achieve high electrochemical performance.
