Hydrothermal synthesize of bi-functional interface structure modified LiMnPO4@LiFePO4/C nanorods as cathode materials for lithium-ion batteries

Olivine-structured LiMnPO4-based cathodes have generated enormous development prospects due to their high energy density, good structural stability, and low cost. However, their scale of application is limited by high electronic and ionic insulativity. In this study, we designed and synthesized a bi-functional interfacial modified composite, 0.9LiMnPO4@0.1LiFePO4/C (0.9LMP@0.1LFP/C), using mechanochemical activation-assisted hydrothermal technology. The innovative Li-storage structure consists of a high-energy density LiMnPO4 (LMP) core, a uniformly coated LiFePO4 (LFP) layer with improved ionic conductivity as the secondary outer shell, and an in-situ coated carbon film with high conductivity as the outermost functional skin. As anticipated, the 0.9LMP@0.1LFP/C composite exhibits outstanding Li-storage properties, demonstrating discharge capacities as high as 157.1 mAh g−1 and 146.7 mAh g−1 at 0.1 C and 1 C rates, respectively. Moreover, it exhibits an ultrahigh capacity retention of 92.5 % after 500 charge and discharge cycles.