Dually Encapsulated LiMn0.6Fe0.4PO4 Architecture with MXene and Amorphous Carbon to Achieve High-performance and Ultra-stable Lithium Battery

Abstract

LiMnxFe1-xPO4 (LMFP) materials, with their high energy density and excellent cycle stability, are promising cathode materials for electric vehicles and other high-energy-density applications. However, the low lithium-ion diffusion coefficient and poor electronic conductivity limit the further development of LMFP. In this study, we designed a strategy involving electrostatic self-assembly and in-situ graphitization to fabricate a dense LMFP@MXene@C structure with dual encapsulation of LMFP (LiMn0.6Fe0.4PO4). Owing to its high degree of graphitization, large surface area, excellent Li-ion directional transport, and dense dual encapsulation structure, the fabricated LMFP@MXene@C cathode exhibits a considerable reversible capacity (153.58 mAh/g after 100 cycles at 1 C) with outstanding rate performance and stability (maintaining 91.26% of its capacity after 1200 cycles at 5 C). According to the detailed TEM, in-situ XRD techniques, and system dynamics and structural stability assessments analysis, the superior electrochemical stability and Li+ transport can be attributed to the network structure formed by 2D MXene layered channels and amorphous C layers. This structure facilitates the rapid electron and ion transfer, effectively providing volumetric buffering and structural protection. The dually encapsulated strategy offers a feasible approach for the preparation of exceptional electrochemical cathode materials.