Enhanced ion transport in CNT-doped PVA/HCl/TEOS electrolyte membranes for aluminium-air batteries

Abstract

This study investigates the impact of carbon nanotube (CNT) incorporation on the electrochemical performance of polyvinyl alcohol (PVA)/HCl/TEOS-based solid polymer electrolytes for rechargeable aluminium-air batteries. CNTs were introduced in varying quantities (0–0.05 g), while a polylactic acid (PLA) nanofiber layer containing carbon quantum dots (CQDs) was integrated as a separator to enhance ion transport. The inclusion of CNTs improved the amorphous structure, as evidenced by X-ray diffraction (XRD), and optimized ionic pathways within the polymer-silica network. The PHT0.05CNT membrane exhibited the highest ionic conductivity of 6.25 × 10⁻³ S cm⁻¹, while transference number analysis confirmed predominant ionic conduction (T_ion = 0.923). Among the tested compositions, PHT0.02CNT achieved the best battery performance, delivering a capacity of 0.4168 mAh g⁻¹ and an energy density of 0.145 mWh g⁻¹. Cyclic voltammetry further demonstrated enhanced redox reversibility with the addition of CNTs. These findings underscore that controlled CNT incorporation significantly enhances ion transport and electrochemical performance, suggesting strong potential for developing high-efficiency aluminium-air batteries.