Nitrogen-doped carbon stabilized LiFe0.5Mn0.5PO4/rGO cathode materials for high-power Li-ion batteries

Abstract

Exploring high ion/electron conductive olivine-type transition metal phosphates is of vital significance to broaden their applicability in rapid-charging devices. Herein, we report an interface engineered LiFe0.5Mn0.5PO4/[email protected] cathode material by the synergistic effects of rGO and polydopamine-derivedN-doped carbon. The well-distributed LiFe0.5Mn0.5PO4 nanoparticles are tightly anchored on rGO nanosheet benefited by the coating of N-doped carbon layer. The design of such an architecture can effectively suppress the agglomeration of nanoparticles with a shortened Li+ transfer path. Meantime, the high-speed conducting network has been constructed by rGO and N-doped carbon, which exhibits the face-to-face contact with LiFe0.5Mn0.5PO4 nanoparticles, guaranteeing the rapid electron transfer. These profits endow the LiFe0.5Mn0.5PO4/[email protected] hybrids with a fast charge–discharge ability, e.g. a high reversible capacity of 105 mAh·g−1 at 10 C, much higher than that of the LiFe0.5Mn0.5PO4@C nanoparticles (46 mA·h·g−1). Furthermore, a 90.8% capacity retention can be obtained even after cycling 500 times at 2 C. This work gives a new avenue to fabricate transition metal phosphate with superior electrochemical performance for high-powerLi-ion batteries.