Performance evaluation of lithium metal rechargeable batteries with a lithium excess cation-disordered rocksalt based positive electrode under high mass loading and lean electrolyte conditions

Abstract

Although lithium excess cation-disordered rock salt (DRX) metal oxides have been identified as promising candidates for positive-electrode materials, their actual potential remains unclear because previous studies have used inappropriate technological parameters, such as low mass loadings or excessive amounts of electrolyte. In this study, Li₂RuO₃/Li₂SO₄ was selected as the model DRX material, and its performance was investigated under cell-level high-energy-density conditions. A highly-mass-loaded positive electrode (30 mg cm⁻²) with an active material ratio exceeding 96% was fabricated by suppression of the gelation of slurry solution during the electrode preparation process, which is achieved by proper control of the particle size of Li₂RuO₃/Li₂SO₄. Notably, using a protected lithium metal electrode setup, superior capacity of the Li₂RuO₃/Li₂SO₄ electrode over 180 mA h g⁻¹ was achieved over the 80th cycle under high mass loading and lean electrolyte conditions. The results obtained in the present study reveal the potential of the DRX based positive electrode for realizing superior performance even under practical cell conditions.