Ionic-electronic dual-conductor interface engineering and architecture design in layered lithium-rich manganese-based oxides

The burgeoning growth in electric vehicles and portable energy storage systems necessitates advances in the energy density and cost-effectiveness of lithium-ion batteries (LIBs), areas where lithium-rich manganese-based oxide (LLO) materials naturally stand out. Despite their inherent advantages, these materials encounter significant practical hurdles, including low initial Coulombic efficiency (ICE), diminished cycle/rate performance, and voltage fading during cycling, hindering their widespread adoption. In response, we introduce an ionic-electronic dual-conductive (IEDC) surface control strategy that integrates an electronically conductive graphene framework with an ionically conductive heteroepitaxial spinel Li₄Mn₅O₁₂ layer. Prolonged electrochemical and structural analyses demonstrate that this IEDC heterostructure effectively minimizes polarization, mitigates structural distortion, and enhances electronic/ionic diffusion. Density functional theory calculations highlight an extensive Li⁺ percolation network and lower Li⁺ migration energies at the layered-spinel interface. The designed LLO cathode with IEDC interface engineering (LMOSG) exhibits improved ICE (82.9% at 0.1 C), elevated initial discharge capacity (296.7 mAh g⁻¹ at 0.1 C), exceptional rate capability (176.5 mAh g⁻¹ at 5 C), and outstanding cycle stability (73.7% retention at 5 C after 500 cycles). These findings and the novel dual-conductive surface architecture design offer promising directions for advancing high-performance electrode materials.