Redox flow batteries, also known as liquid batteries, store electrical energy in dissolved chemical compounds. They are regarded as an alternative to lithium-ion batteries, especially for stationary energy storage. A team led by Prof. Dr. Ingo Krossing from the Institute of Inorganic and Analytical Chemistry at the University of Freiburg has succeeded in developing a non-aqueous all-manganese flow battery (all-MFB) whose active components use sustainably available manganese and have a long lifetime. The researchers present the results of their work in the current issue of Advanced Energy Materials .

Active materials are the chemical substances needed for energy storage in batteries. The Freiburg scientists have now replaced the element vanadium, which was previously used as the active material, with the readily available manganese. Krossing and his team pursued a new approach to make the sustainable manganese work in the battery: coupling the deposition of elemental manganese with the oxidation of manganese in the +II oxidation state to manganese +III has not been used before to store energy electrochemically. The newly developed battery achieves an energy density that is about twice as high as that of the previous standard redox flow battery with vanadium.

“With the electrolytes presented in our publication, energy densities of up to 74 Wh L^-1 are possible,” explains Krossing. “In the first experiment, this is already much better than the energy density of the vanadium redox flow battery, which has been researched since 1978.” Although further optimisation of the battery is still necessary, says the Freiburg chemist, “this system describes a completely new and promising structure for sustainable stationary energy storage.”

Original publication:
Schmucker, M. et al., Krossing, I. (2021): Investigations Towards a Non-Aqueous Hybrid Redox-Flow Battery with a Manganese Based Anolyte and Catholyte. In: Advanced Energy Materials. DOI: 10.1002/aenm.202101261