摘要
The commercialization of silicon-based anodes is affected by their low initial Coulombic efficiency(ICE)and capacity decay,which are attributed to the formation of an unstable solid electrolyte interface(SEI)layer.Herein,a feasible and cost-effective prelithiation method under a localized highconcentration electrolyte system(LHCE)for the silicon-silica/graphite(Si-SiO_(2)/C@G)anode is designed for stabilizing the SEI layer and enhancing the ICE.The thin SiO_(2)/C layers with-NH_(2) groups covered on nano-Si surfaces are demonstrated to be beneficial to the prelithiation process by density functional theory calculations and electrochemical performance.The SEI formed under LHCE is proven to be rich in ionic conductivity,inorganic substances,and flexible organic products.Thus,faster Li+transportation across the SEI further enhances the prelithiation effect and the rate performance of Si-SiO_(2)/C@G anodes.LHCE also leads to uniform decomposition and high stability of the SEI with abundant organic components.As a result,the prepared anode shows a high reversible specific capacity of 937.5 mAh g^(-1)after 400 cycles at a current density of 1 C.NCM 811‖Li-SSGLHCE full cell achieves a high-capacity retention of 126.15 mAh g^(-1)at 1 C over 750 cycles with 84.82%ICE,indicating the great value of this strategy for Si-based anodes in large-scale applications.
基金
National Natural Science Foundation of China,Grant/Award Number:22179006
Natural Science Foundation of Zhejiang Province,Grant/Award Number:LQ23E020002
National Natural Science Foundation of China,Grant/Award Numbers:52202284,52072036
Cooperation between Industry and Education Project of Ministry of Education,Grant/Award Number:220601318235513
WenZhou Natural Science Foundation,Grant/Award Numbers:G20220019,G20220021
State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Grant/Award Number:EIPE22208
Key Research and Development Program of Henan province,China,Grant/Award Number:231111242500。
