Polyamide gel electrolytes based on AlCl3/guanidine hydrochloride ionic liquid analogue electrolytes for high-performance aluminum batteries

Rechargeable aluminum-ion batteries (AIBs) offer a compelling alternative to lithium-ion systems due to aluminum's abundance, high theoretical capacity, and cost advantages. However, conventional AlCl 3 -based electrolytes suffer from leakage, corrosiveness, and extreme moisture sensitivity, which degrade Coulombic efficiency and cycling stability. This study addresses these issues by developing a polyamide-based gel polymer electrolyte (PAGPE) incorporating a low-cost AlCl 3 /guanidine hydrochloride (Guan) ionic liquid analogue electrolyte. The PAGPE, formed by blending polyamide (PA6) with the AlCl 3 /Guan electrolyte, enhances thermal stability, moisture resistance, and electrochemical performance. In Al-graphite cells, the gel electrolyte achieves high rate capability, long-term cycling stability, and nearly 99 % Coulombic efficiency. The PAGPE also significantly mitigates corrosion and moisture-induced degradation compared to its liquid counterpart. Furthermore, when applied to aluminum-sulfur (Al-S) batteries, the gel electrolyte effectively suppresses the polysulfide shuttle effect. Oxidation-type Al-S cells deliver ∼600 mAh g −1 , while reduction-type cells reach ∼1000 mAh g −1 , both with high efficiency and improved cycling behavior. These results demonstrate the feasibility of Guan-based PAGPEs as robust, scalable electrolytes for next-generation aluminum-based energy storage systems.