A novel Al@TiO2-MCMB dual-ion battery with excellent cycling performance at high current rate

Abstract

A novel dual-ion battery (DIB) constructed with Al@TiO2 (core@shell) as anode and mesocarbon microbead (MCMB) as cathode was prepared, and it was based on an ordinary commercial lithium-salt organic electrolyte. The nanoscale Al@TiO2 anode is composed of an inner aluminum nanosphere and an anatase TiO2 outer shell with a tunable interspace, which can provide enough space for the volume expansion of Al nanosphere during the Li–Al alloying reaction. MCMB cathode can solve the problems of excessive swelling, collapse and failure during charge and discharge process of graphite layers caused by anisotropy of graphite. This novel Al@TiO2-MCMB DIB demonstrates significantly enhanced electrochemical performance. It possesses a discharge capacity of 100 mAhg−1, 98.1% capacity retention, and >95.7% coulombic efficiency after 1000 cycles under discharge rate of 5C (1C corresponding to 372 mA g−1). As a contrast, the capacity of general DIBs is ≈ 100 mAhg−1 at a current rate ≤200 mAg−1. Furthermore, the Al@TiO2-MCMB DIB delivers a high specific energy of ≈198 W h kg−1 at a power density of 1523 W kg−1 at 5C. In addition, the novel DIB reduces the dependence on nonrenewable lithium resources, but using abundant aluminum and titanium.