Influence of LiFSI on Rate Capability of Lithium-Ion Battery

Lithium bis(fluorosulfonyl)imide (LiFSI) has been investigated as a conducting salt of liquid electrolytes for lithium-ion batteries (LIBs). It shows higher decomposition temperature and Li⁺ conductivity than LiPF₆. LiNi_1-x-yCo_xAl_yO₂ (0<x,y<1) is one research focus on LIB cathode materials for its high discharge specific capacity and excellent cycle life. In this article, LiFSI is used as main salt in Li_0.8Co_0.15Al_0.05O₂ (NCA) /graphite LIBs to enhance rate capability. NCA/graphite LIBs with LiPF₆-based organic electrolyte show 95.3% capacity retention at 1C discharge rate and 89.6% at 3C discharge rate, whereas discharge capacity retention of LiFSI-based ones is 96.7% at 3C.