Aluminum–graphite dual ion batteries (AGDIB) are cost effective in development because they employ inexpensive materials such as aluminum and graphite. Ionic liquids—specifically anolytes—serve as electrolytes, e.g., mixtures of 1 ethyl 3 methylimidazolium chloride ([EMIm]Cl) and aluminum trichloride (AlCl3). A composition with [EMIm]Cl:AlCl3 at 1:1.5 delivers very good performance, also TEA and urea based electrolytes are also suitable [1]. During charging, aluminum is electrodeposited on the aluminum anode from Al2Cl7– present in the electrolyte, while AlCl4– intercalates into the graphite cathode. A single cell achieves a power density of 9 kW/kg (based on graphite), and laboratory cells readily reach lifetimes of 25,000 cycles at high charge/discharge rates with a published record of 500,000 cycles [2].
For practical deployment, a pouch cell design was developed, exhibiting resistance to electrolyte corrosion via an internal PE layer. Continued development yielded a four layer pouch cell with a total nominal capacity up to 200 mAh, a cycle life of up to 1,000 charge–discharge cycles at 6 C and a discharge capacity of 120 mAh. Stability of the cell components was analyzed using post mortem microscopy and spectroscopy, revealing complete dissolution of the aluminum anode at end of life and a remaining black residue. Preliminary demonstrators incorporating these cells are planned. The capacity can reach up to 1.7 Ah at a nominal voltage of 7.6 V. With a maximum current draw of 19 A, 150 W of power can be achieved. To achieve these values, the battery cells can be connected in up to a 4S11P configuration. The battery module will be managed by a foxBMS battery management system for monitoring, and load profiles for applications such as uninterruptible power supplies (UPS) are simulated under real conditions