Few‐Layered ReS₂@CNTs as a High‐Performance Cathode for Aluminum‐Ion Batteries

Abstract With a high theoretical specific capacity of 2978 mAh g⁻¹, rechargeable aluminum‐ion batteries (AIBs) are considered as promising next‐generation energy storage devices with higher electrochemical performance. Nevertheless, the search for stable cathode materials with outstanding capacity and rate performance remains elusive. In current work, few‐layered ReS₂ is in situ grown on carbon nanotubes (CNTs) to form the ReS₂@CNTs composite. As ReS₂ features a large interlayer spacing of ≈0.65 nm, the extremely weak interlayer coupling can effectively reduce the electrostatic repulsion between Al³⁺ ions and the cathode host, adequately accommodating large amounts of Al³⁺ ions without significant volume expansion. When it serves as the cathode in the AIB, ReS₂@CNTs delivers a high discharge specific capacity of 396.3 mA h g⁻¹ and Coulombic efficiencies of ≈100% both after 250 cycles at a low rate (200 mA g⁻¹) and 10 000 cycles under a higher rate (1 A g⁻¹). Theoretical simulations and ex situ grazing incidence angle X‐ray diffraction results reveal that Al³⁺ cations can be favorably and reversibly intercalated/deintercalated into the ReS₂@CNTs during the discharge/charge process. This work provides new insights into AIB chemistry and paves the way for the development of high‐performance AIBs.