Construction of Interlayer-Expanded MoSe<sub>2</sub>/Nitrogen-Doped Graphene Heterojunctions for Ultra-Long-Cycling Rechargeable Aluminum Storage
Xiaoqiong Feng, Jianmei Li, Jianmei Li, Yunlong Ma, Chunyan Yang, Shiying Zhang, Jinfeng Li, Jinfeng Li, Changsheng An
Abstract
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.