Enhanced Performance of Lithium Polymer Batteries Based on the Nickel-Rich LiNi_0.8Mn_0.1Co_0.1O₂ Cathode Material and Dual Salts

We report a 4 V-class cathode of layered nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) for use in poly(ethylene oxide) (PEO)-based lithium polymer batteries. A semi-interpenetrating polymer network (semi-IPN) PEO-based solid polymer electrolyte (SPE) is prepared by the in situ thermal cross-linking of a precursor solution containing a lithium salt, poly(ethylene glycol) dimethyl ether as the plasticizer, and bisphenol A ethoxylate diacrylate as the cross-linker. Using the dual salts of lithium bis(trifluoromethane)sulfonamide and lithium bis(oxalate)borate (LiBOB), the formation of a dense and stable solid electrolyte interface on the Li-metal anode leads to reduced electrolyte decomposition and suppresses Li dendrite formation during cycling. Moreover, LiBOB provides an effective cathode–electrolyte interface, which efficiently protects the NMC811 particles from cracking. Consequently, the cycling performances of the NMC811-based lithium polymer batteries are significantly enhanced. At 45 °C, with a high loading density of the active material, the NMC811/SPE/Li-metal battery delivers a specific discharge capacity of 166 mAh g–1 at 0.1C. Furthermore, the capacity of the cell remains at 82% after 200 cycles at 0.5C. These outstanding results demonstrate the potential for the practical application of NMC811-based lithium polymer batteries with enhanced energy densities and safety profiles.