As a result of the ongoing energy revolution, the development of new battery types with new cell chemistries gained a lot of attention in the last five to ten years. This evolution is on one side triggered due to the gap between demand and supply of required resources like lithium, nickel, and cobalt. This gap led to a huge cost-rally of the raw materials, e.g. the price of lithium was very volatile within the last 5 years.1, 2 The search for other cheap, reusable, and above all, safe sustainable cell chemistries led. among other things, to the development of rechargeable sodium-ion batteries (SIBs). Other cell chemistries that show promising properties are zinc-ion batteries (ZIBs) and potassium-ion batteries (KIBs) but these are not commercialized yet.
One of the raising stars that gained attention in the last few years is the so-called aluminum-graphite-dual-ion battery (AGDIB). The active materials are aluminum as inexpensive anode and natural graphite as cathode material. During charging, chloroaluminate anions intercalate into the graphite host-matrix, while at the anode, metallic aluminum from the electrolyte is deposited, see equation (1) and (2). Typical electrolytes, which are in research focus, are the so-called ionic liquids made of 1-ethyl-3-methyl-imidazoliumchloride [EMIm]Cl and AlCl3 or triethylamine hydrochloride [TEA]Cl and AlCl3.3, 4 Other electrolytes belong to the group of so-called deep-eutectic solvents e.g., a mixture of urea and AlCl3.5 Thus, less toxic than common electrolytes in other chemistries.
Cathode C_N+AlCl_4^- □(↔┴(de)intercalation [C_N AlCl_4 ]+e^- ) (1)
Anode 4 Al_2 Cl_7^-+3 e^-↔Al^0+7 AlCl_4^- (2)
Beside the mentioned advantages (cheap raw materials and urea based electrolytes), the AGDIB can be operated with extraordinary high-power densities up to 9 kW kg_Graphite^(-1) as shown in laboratory scaled battery cells.6 Thus, together with an extraordinary long cycle life >25.000 cycles in lab test cells, the AGDIB might be a game-changer for high power applications.
To push the technical-readiness-level (TRL), we focused on upscaling processes aiming at higher loadings & multilayered pouch cells. This involved optimization of selected pouch cell casing materials as well as a detailed study on adjusting the effective graphite loading, evaluating binders and slurry recipes together with a controlled porosity of the prepared electrodes. We increased the active graphite loading from 5 mg cm^(-2) to 15,0 mg cm^(-2) employing a sodium alginate binder, while the prepared electrodes showed a mean capacity up to 80-100 mAh for a 2-layered cell. The results are supported by in-depth electrochemical characterization like cyclic voltammetry (CV), U/I curves and electrochemical impedance spectroscopy (EIS). To allow further upscaling, the specifics of cells in the ampere-hour range have been determined.
To enhance the kinetics of electrochemical Al-plating and stripping mechanism, as suggested by other groups7, we analyzed commercially available Al-alloys by CV, chronopotentiometry (CP) and EIS to push the high-power properties of the developed AGDIB.
Those new pouch cells show an extraordinary cycling stability above 3,000 cycles at 10C while increasing the energy efficiency and rate capability.

For the first time the AGDIB is also tested with a typical power-profile for grid-stabilization. In addition, the AGDIB was evaluated for a potential application that matches the performance characteristics – the provision of instantaneous reserve. This profile consists of short, highly dynamic pulse loads over several hours and has been used at 20 °C and 30 °C and scaled to 1 and 5C. Simulation of these tests with a parameterized model completed the evaluation The results confirm the applicability of AGDIB for dynamic grid-stabilization and thus their possible contribution in providing a stable energy supply employing renewable, yet fluctuating energy sources.
The data obtained are of fundamental importance for increasing the TRL and represent the first step towards a possible commercially usable rechargeable AGDIB.