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

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.