The German Bundesministerium für Bildung und Forschung (BMBF) has earmarked 3.3 million euro for the project over three years.

The use of a water-based electrolyte also guarantees a high level of safety, says ZSW, and “they are cheap, with material costs of 15 to 50 euro per kWh for such batteries undercutting the comparable values for lithium–ion batteries by a factor of two to three.”

Zinc–manganese dioxide batteries are in widespread use and the global standard for non-rechargeable cells, but not yet available in rechargeable form. The ORRCABATT project partners want to change this.

Although specific energy densities of zinc– manganese, up to 400 watt-hours per litre or 150 watt-hours per kg, are less than zinc–manganese dioxide batteries, they can still be an efficient and inexpensive way of storing power, ZSW argues. Other outstanding features are extremely low susceptibility to overheating and non- combustibility.

A key milestone for ORRCABATT (Optimised design for rechargeable and recyclable alkaline MnO2 batteries) will be production of a prototype cell with an energy density of over 100 watt- hours per kg capable of more than 150 charge/ discharge cycles. There are also plans to develop a demonstration battery with an energy capacity of over one kilowatt-hour.

ZSW has already developed higher energy density rechargeable zinc–manganese dioxide batteries by employing innovative membrane technology and further system adaptations. These first prototypes boast exceptional cycle stability, which translates to a long service life.

As part of ORRCABATT, the best materials will be identified on the basis of life cycle assessments and appropriate recycling routes will be developed with the specific requirements of the selected materials in mind. This will “enable a full assessment of the environmental impact right from the start and a recycling system fit for the future,” says ZSW.

The project partners include TU Braunschweig, Justus Liebig University Giessen, Institute for Decentralized Electrification, Entrepreneurship and Education, and VARTA. The associate partners are FUMATECH BWT and GRILLO-Werke.