Binder-Free FeS₂@CNT Self-Supported Film as Cathode for Chloride Molten Salt Aluminium Batteries

Rechargeable molten salt aluminium batteries have emerged as a highly promising candidate technology for large-scale energy storage systems, owing to their high energy density, low cost, and excellent cycling stability. This study aims to improve the elec-trochemical performance of chloride molten salt aluminium batteries by addressing the limitations of FeS 2 cathode material, including particle agglomeration, volume expan-sion, and poor conductivity. FeS 2 and FeS 2 @CNT were prepared using hydrothermal and in-situ growth methods, respectively, with comprehensive characterisation and elec-trochemical techniques. By forming a unique “point-line” contact structure with F-CNT, it enhances ion diffusion and structural stability, providing a pathway for electron transport. In terms of electrochemical performance, FeS 2 @CNT significantly outper-forms pristine FeS 2 : excellent initial discharge specific capacity (191.2 mAh g −1 at 0.5 A g −1 ), reduced polarization (ΔEp = 0.10 V at 0.1 mV s −1 ), outstanding rate performance (151.5 mAh g −1 at 1 A g −1 ), and exceptional cycling stability (89.6% capacity retention after 800 cycles at 0.5 A g −1 ). Ex-situ tests confirmed the reversible insertion/extraction process of AlCl 4 − , revealing the energy storage mechanism. The in-situ growth strategy constructs a F-CNT conductive network, significantly enhancing the conductivity of FeS 2 (Rct = 0.88 Ω), offering a novel pathway to optimize sulphide cathodes for high-performance RABs.