In-situ construction of extra ion-store sites and fast ion-diffusion channels for lithium-rich manganese-based oxides cathode

Lithium-rich manganese-based oxides (LRMO) are very promising cathode materials for next-generation high-energy-density Li-ion batteries, but their application is hindered by the inherent low initial Coulombic efficiency (ICE) (<80%), poor cycling stability, and rate performance. Herein, we solve these bottlenecks via in-situ constructing a P2-type Na0.66MnO2 phase on the surface of LRMO particles (LRMO/P2) using a two-step coprecipitation and one-step co-firing strategy. The P2-type Na0.66MnO2 phase offers extra ion-store sites for LRMO particles to offset the irreversible capacity loss in the first cycle, which improves the ICE to above 92%. It can also provide a fast ion-diffusion channel with a low Li-ion diffusion energy barrier, which effectively raises the discharge capacity. The developed LRMO/P2 cathode delivers a high reversible capacity of 243 mAh·g−1 at 1 C with a retention of 80% after 240 cycles. This works gives new insights into developing high-performance cathode materials for high-energy-density batteries.