Effects of LiFSi and LMO-Coated NCM on Capacity and Cycle Characteristics of All-Solid Lithium Batteries

Abstract

The initial capacity and cycle retention properties of all-solid lithium batteries (ASLBs) were greatly improved by utilizing polyethylene oxide (PEO)/lithium salts in conjunction with LiFSi, and coating the nickel manganese cobalt oxide (NCM) cathode component with lithium manganese oxide (LMO). That is, composite cathodes for ASLBs were fabricated by using lithium salts (LiClO4/LiFSi (8:2)) with PEO, Al-LLZO powder, Super-P, and LMO-coated NCM-424/622, respectively (Al-LLZO = Li6.25Al0.25La3Zr2O12). LiFSi was added to a solution of PEO/LiClO4 ([EO]:[Li] = 13:1) to generate a composite cathode and composite solid electrolyte (CSE) sheet. The initial capacity and cycle retention of the resulting cells were improved by controlling the side reactions and the improving kinetic characteristics. Moreover, NCM-424 and NCM-622 were coated with LMO; the optimum LMO coating amount (1 wt%) and NCM-424/622 ratio (9:1) for simultaneously improving the capacity and cycle retention were explored. Overall, the initial capacity of the ASLBs reached 152 mAh g−1, with a capacity retention rate of 92% at the 100th cycle.