▎ 摘　　要

At present, because of the low energy density of aluminium-based batteries, rGO coated porous nanospheres TiO2@Se (TiO2@Se-rGO) was prepared by electrostatic effect as cathode material for Al-Se batteries. In Al-Se batteries, rGO coating has three functions: firstly, rGO uniform coating improves the dynamic properties of electrons and ions by increasing the diffusion or transfer rate; secondly, it avoids the diffusion of some selenides and dissolves them into the electrolyte to affect the electrochemical properties; lastly, the coating can stabilize the nanostructure and avoid the volume expansion or structural collapse during cycling. In addition, the porous nanosphere TiO2 provides sites for the redox reaction of selenium, and can also avoid the dissolution of selenide. Most importantly, the density functional theory (DFT) shows that compared with TiO2(101), Se(101) has a larger adsorption energy of [AlCl4](-) and a smaller diffusion barrier of [AlCl4](-). Therefore, TiO2@Se-rGO exhibits excellent electrochemical performance in Al-Se batteries. The initial discharge capacity reaches 1127.3 mAh g(-1) at 0.2 A g(-1), and the capacity is 208.7 mAh g(-1) even at 1 A g(-1). The discharge capacity is still as high as 225.8 mAh g(-1) after 500 cycles at 0.5 A g(-1). Therefore, TiO2@Se-rGO shows a clear advantage in the cathode material of aluminum-based batteries.