Cobalt-doped TiO2@C hierarchical nanocomposites derived from Ti3C2 MXene as cathodes for hybrid magnesium-lithium batteries
Xiaohui Li, Yakun Tang, Lang Liu, Yue Zhang, Yang Gao, Mao Qian, Wenjie Ma
Abstract
TiO 2 has been explored in hybrid magnesium-lithium batteries (HMLBs) due to the advantages of low self-discharge and small volume expansion during ion insertion. However, how to improve the inherently low ionic and electrical conductivity of TiO 2 is the problem that needs to be solved. In this work, a smart strategy is adopted to prepare cobalt-doped TiO 2 @C (Co 4+ -TiO 2 @C) hierarchical nanocomposite derived from Co(II)(OH) n @Ti 3 C 2 . Compared with TiO 2 @C (without cobalt doping), Co 4+ -TiO 2 @C shows the highest specific capacity (154.7 mAh·g − 1 at 0.1 A·g − 1 after 200 cycles) and extraordinary rate performance in HMLBs. The excellent electrochemical performance of Co 4+ -TiO 2 @C is ascribed to the synergistic effect of the hierarchical structure and cobalt-doping. Both experimental results and density functional theory (DFT) calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the Li + migration barrier. This work provides a new insight to design TiO 2 -based cathode materials with high-performance in HMLBs.