MoC@Cu@C composites with structural advantages exhibit excellent electrochemical performance and stability in LIBs

Abstract

Herein, we synthesized a porous carbon matrix composite (MoC@Cu@C) by pyrolyzing a compound consisting of a copper-based metal organic framework materials and a molybdenum-based polyoxometalate under nitrogen atmosphere. This is a mesoporous molybdenum carbide octahedron consisting of extremely small nanocrystals. Owing to the porous nature of the composite material and its surface-rich carbon matrix, it is believed to provide more active Li+ storage sites, which can enhance electrical conductivity and effectively inhibit volume expansion during cycling. Furthermore, the in-situ synthesis of copper in the sample can bring additional conductivity enhancement and good initial lithium deposition kinetics, doping of heteroatom N in organic ligands brings additional capacity. Benefit from this, the MoC@Cu@C anode shows good rate and cycling performance. When the battery is cycled 100 times at a current density of 100 mA g−1, it can achieve 100 % capacity retention with a high reversible capacity of 820 mAh g−1. Even when cycled at 2000 mA g−1, the capacity stabilizes at 526 mAh g−1, of which 98 % is retained after 1000 cycles. These features make the MoC@Cu@C composites a promising new generation of anode materials for LIBs.