Abstract
Layered lithium nickel-cobalt-manganese oxides(NCM)have been highlighted as advanced cathode materials for lithium-ion batteries(LIBs);however,their low interfacial stability must be overcome to ensure stable cycling performance of the cell.In this work,we propose a one-step surface modi-fication method that uses a task-specific precursor,N,N,N,N-tetraethylsulfamide(NTESA),to improve interfacial stability of Ni-rich NCM cathode materials.The unstable surface properties of Ni-rich NCM cathode material are improved by embedding an artificial cathode-electrolyte interphase(CEI)layer on the cathode surface by heat treatment of the Ni-rich NCM cathode material with an NTESA precursor at low temperature.Our material analyses indicate that this approach allows the formation of amine-and sulfone-functionalized CEI layers on the surface of Ni-rich NCM cathode material without changing the layered structure of the cathode material.NTESA-functionalized Ni-rich NCM cathode materials exhibit improved cycling retention after 100 cycles:for example,a cell cycled with a 3.0 NTESA-modified NCM811 cathode presents the highest retention ratio of 88.3％,whereas a cell cycled with a non-functionalized NCM811 cathode suffers from rapid fading of the cycling performance(68.4％).Our additional SEM,XPS,and EIS analyses indicate that electrolyte decomposition is suppressed during electrochemical cycling,thereby leading to smaller increases in the internal resistances.ICP-MS analyses of the cycled anodes also indicate that the NTESA-based artificial CEI layer inhibits the dissolution of transition metal components from the Ni-rich NCM cathode materials,thereby contributing to an improved overall electrochemical performance of the cell.
基金项目
This work was financially supported by the National Research Foundation of Korea(NRF)(NRF-2019R1C1C1002249)
and the Technology Innovation Program(Nos.20010095)
and the Technology Innovation Program(20011905)
funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)()
NETL
NSTL
维普
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