Toluene-containing mixed alkylamine hydrochloride–AlCl3 electrolyte for high-performance aluminum–anthraquinone batteries

A low-cost chloroaluminate electrolyte combining high ionic conductivity with suppressed active-material dissolution is desirable for Al–organic batteries. In this study, a toluene-containing mixed alkylamine hydrochloride–AlCl 3 electrolyte, denoted Tol–MACl–AlCl 3 , was developed for Al || anthraquinone (AQ) batteries. Toluene addition effectively reduced the viscosity of MACl–AlCl 3 and increased its ionic conductivity. The optimized Tol–MACl–AlCl 3 electrolyte exhibited an ionic conductivity of 21.6 mS cm −1 at 28 °C, higher than that of the conventional EMImCl–AlCl 3 electrolyte, while its estimated material cost was approximately one-tenth that of EMImCl–AlCl 3 . Cyclic voltammetry and galvanostatic electrodeposition analyses confirmed the occurrence of reversible Al plating and stripping in the toluene-containing electrolyte. In addition, AQ displayed lower saturated solubility in the MACl-based and toluene-containing electrolytes than in EMImCl–AlCl 3 , indicating that optimized electrolyte compositions can help suppress dissolution of the organic cathode material. When Tol–MACl–AlCl 3 was used as the electrolyte, the Al || AQ cell delivered an initial discharge capacity of 189 mAh g −1 and retained 122 mAh g −1 after 100 cycles at 100 mA g −1 , markedly outperforming the conventional Al | EMImCl–AlCl 3 | AQ cell. These results demonstrate that Tol–MACl–AlCl 3 improves Al || AQ cell performance through both enhanced ion transport and reduced AQ dissolution, positioning electrolyte optimization as an effective strategy for developing low-cost Al–organic batteries.