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

摘要

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 electro-chemical 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 approximate to 100 mA hg(-1) at a current rate <= 200 mAg(-1). Furthermore, the Al@TiO2-MCMB DIB delivers a high specific energy of approximate to 198Wh kg(-1) at a power density of 1523Wkg(-1) at 5C. In addition, the novel DIB reduces the dependence on nonrenewable lithium resources, but using abundant aluminum and titanium. (C) 2019 Elsevier B.V. All rights reserved.