Enhanced Performance of Lithium Polymer Batteries Based on the Nickel-Rich LiNi0.8Mn0.1Co0.1O2 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 degrees 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.