Upgrading Electrode/Electrolyte Interphases via Polyamide-Based Quasi-Solid Electrolyte for Long-Life Nickel-Rich Lithium Metal Batteries

Interface instability that stems from highly catalytic Ni-rich layered cathode and highly reactive lithium metal anode is the key to hindering the development of high-voltage lithium metal batteries (LMBs). Herein, we designed a multifunctional polyamide-based quasi-solid electrolyte (PAM-QSE) to construct a robust cathode electrolyte interphase (CEI) and stable solid electrolyte interphase (SEI) layers on both Ni-rich cathode and Li metal anode and improve flame-retardancy simultaneously. The SEI structure consists of rich lithiophilic N–(C)3 to homogenize ion distribution and high ionic conductive Li3N to guide the rapid transform of Li+, effectively reshaping the uneven Li+ plating/stripping behavior, whereas the CEI structure comprises high antioxidative amide organic species, which mitigates the detrimental parasitic reactions between active materials and electrolytes and alleviates surface structure degradation of cathode. As a result, LiNi0.6Co0.2Mn0.2O2/Li battery using flame-retardant PAM-QSE delivers excellent long-term cyclability even with high cathode loading (∼6 mg cm–2) and ultrathin Li (∼50 μm).