Stationary energy storage systems will play a pivotal role in energy transition, but they must be stable, sustainable, affordable and have long life. The prevalent technology lithium-ion (li-ion) batteries do not meet all these requirements. But now an international collaboration between the MEET Battery Research Centre at the University of Münster (WWU), North Rhine-Westphalia, and the Pacific Northwest National Laboratory (PNNL) in Washington, USA, has produced a novel type of “dual-ion” battery in the laboratory which has several advantages.

Dr Tobias Placke, group leader of materials at MEET, explains in a press release that by using a unique chemical composition of graphite/zinc in the electrode with a “specially developed aqueous electrolyte” the new technique showed distinct “advantages with respect to cost, sustainability and safety compared to lithium ion batteries, due to the materials used.”

The cathode of the device can be made of graphitic carbons, which come from renewable raw materials. The biological binders in the electrolyte – which are similar to those found in yoghurt – can also be sustainably and cheaply sourced. Finally, zinc is more readily available than lithium.
Up until this point, the energy density of dual-ion batteries could not compete with li-ion, but the new system shows high electrochemical performance. “In our investigations, we were able to successfully elucidate basic mechanisms for anion intercalation in graphite in an aqueous-based system by means of experimental work and computer simulations. We have thus gained important insights for further research on dual-ion technology for grid level energy storage," says Dr Ismael Rodríguez-Pérez from PNNL in a press release.
The detailed results of the experiments were first published in the open access journal Advanced Energy Material.