摘要
Comprehensive Summary Layered transition-metal oxides are promising cathode candidates for sodium-ion batteries.However,the inferior interphase formation and particulate fracture during sodiation/desodiation result in structure degradation and poor stability.Herein,the interface chemistry of P2-Na_(0.640)Ni_(0.343)Mn_(0.657)O_(2)in an electrolyte of 1.0 mol/L NaPF6 in diglyme is unveiled to enable highly reversible Na extraction and intercalation.The uniform and robust cathode-electrolyte interphase layer is in situ formed with decomposition of diglyme molecules and anions in initial cycles.The NaF-and CO-rich CEI film exhibits high mechanical strength and ionic conductivity,which suppresses the reconstruction of its electrode interphase from P2 phase to spinel-like structure and reinforces its structure integrity without cracks.This favours facile Na+transport and stable bulk redox reactions.It is demonstrated to show long cycling stability with capacity retention of 94.4%for 180 cycles and superior rate capability.This investigation highlights the cathode interphase chemistry in sodium-ion batteries.
基金
the National Natural Science Foundation of China(52171215)
Haihe Laboratory of Sustainable Chemical Transformations,and China National Postdoctoral Program for Innovative Talents(BX2021024)。
