▎ 摘　　要

Owing to their low cost and abundant reserves, aluminum-ion batteries (AIBs) have been considered a potential candidate for future large-scale storage applications. However, AIBs are still in the stage of intensive research due to their cathodes of limited specific capacity, energy density, and cycling stability. In this work, interlayer-expanded MoSe2/nitrogen-doped graphene (MoSe2/N-G) heterojunctions with fewer layers and fine dispersion are synthesized by a facile hydrothermal method. Experimental verification and theoretical calculation reveal that the unique heterojunction structure and hetero-element doped graphene conductive network are beneficial for improving the electrochemical reaction kinetics and provide more active vacancies for AIBs, as well as slow the structural degradation during the discharge/charge process. When serving as a cathode material for AIBs, the as-prepared MoSe2/N-G electrode presents a high specific capacity of 167 mAh g(-1) at 0.2 A g(-1). Meanwhile, the hybrid also exhibits excellent cycling stability (140 mAh g(-1) at 0.2 A g(-1) after 1000 cycles) with a high Coulombic efficiency of 99.54% and less than 16% loss of discharge capacity. As verified by ex situ X-ray photoelectron spectroscopy (XPS)/transmission electron microscopy (TEM) characterization and first-principles calculations, the Al3+ intercalation mechanism of the MoSe2/N-G electrode in AIBs are further confirmed.