Modulating the electrode-electrolyte interphases for high-energy lithium-metal batteries

Abstract

Pairing high-loading Ni-rich layered oxide cathodes with Li-metal anodes offers a promising strategy toward high-energy Li-metal batteries. However, structural instability and surface reactivity of both electrodes induce parasitic reactions with the electrolyte solution, particularly under high charging rate conditions, leading to rapid capacity degradation. Herein, a dual-additive-incorporated carbonate-based electrolyte solution is developed for the stable cycling of Li-metal batteries, featuring a high-loading Li[Ni0.9Co0.05Mn0.05]O2 cathode under lean electrolyte and high charging rate conditions. The individual and combined effects of lithium difluorophosphate (LiDFP) and lithium nitrate (LiNO3) are systematically investigated to elucidate their influence on the cycling behavior of Li-metal batteries. The synergistic effect of LiDFP and LiNO3 modulates the electrolyte-electrode interphase (EEI) layer to be robust and conductive, suppressing dendritic Li growth and structural degradation of the cathode. This study also highlights the importance of suppressing the crossover effect for Nirich cathode-based Li-metal batteries. The Li||Li[Ni0.9Co0.05Mn0.05]O2 Li-metal full cell with a areal capacity of 4.6 mAh cm-2 and lean electrolyte condition delivers a high discharge capacity of 230.0 mAh g-1 at 0.1 C, maintains stable cycling over 200 cycles with a cycle retention of 85.4 %, and exhibits an average Coulombic efficiency of 99.87 % at high rate conditions.