The roadmap addresses a number of pressing questions regarding alternative battery technologies:

• What are the technological advantages of alternative battery technologies? Many types of alternative batteries, such as metal-ion (e.g., sodium-ion or zinc-ion) or metal-air (e.g., zinc-air) batteries, show great potential for increased sustainability, lower costs, or reduced resource consumption, but some also have disadvantages such as lower energy density or limited technology maturity. Metal-sulfur batteries, for example, could have a higher energy density and their cost is expected to be much lower than that of LIBs due to the moderate cost of sulfur per kWh. Redox flow batteries are already available on the market, however, they still need to improve in terms of cost and carbon footprint.
• What are the potential applications for alternative battery technologies? For mobile applications, sodium-ion batteries are on the verge of widespread commercialization, and the first sodium-ion batteries are already being used in electric two-wheelers and small cars. Lithium-sulfur batteries potentially could be used in larger drones from 2035 and even more aviation applications from 2040. For stationary applications, the requirements, for example, in terms of energy density are lower. In such cases, storage systems like redox flow batteries, salt water or sodium-sulfur high-temperature batteries, some of which are already available on the market, are likely to become more relevant in the near future - similar to sodium-ion, zinc or aluminum-ion batteries which are notable for their good resource availability, safety or deep discharge capability.
• Are there alternative battery technologies that significantly reduce the dependence on raw materials? Some promising alternative battery technologies do require larger amounts of raw materials to achieve the same storage capacity due to their comparatively lower energy density. However, many of the non-lithium based technologies require less critical raw materials for this than LIBs. Nevertheless, given the absence of any sizeable areas of application or markets, the production and supply of lithium, nickel and cobalt is expected to remain critical for the time being – particularly over the next 5 to 10 years.
• Are there any alternative battery technologies on the horizon that can be produced and scaled in a similar way to LIBs? Over the coming decade non-LIB metal-ion batteries look promising in this regard because their production steps are very similar to those of LIBs. Existing production technologies and environments could be used directly (so called drop-in technologies) or would only require minor modification.
• Are alternative battery technologies likely to become less expensive than LIBs? Although alternative battery technologies potentially have lower material costs than LIBs, their cell costs are likely to be higher initially due to the low volume of production. Scaling production brings significant cost benefits, but this depends on whether there are sufficiently large markets and applications on a GWh scale.
• How is Europe positioned when it comes to alternative battery technologies? Patent and publication analyses show that EU countries are better positioned for redox flow batteries, lithium-air and aluminum-ion batteries, for example, than they currently are for LIBs – for which Japan and China are still the frontrunners. For some alternative battery technologies, EU countries show dynamic annual growth rates of between 10 and 50 percent, while for LIB the growth rate is around 10 percent.

Dr. Annegret Stephan, scientific coordinator of the roadmap at Fraunhofer ISI, also highlights the need for support from policymakers in order to fully exploit the potential of alternative battery technologies: “Especially in the early stages, when the development of future markets is still uncertain, incentives for industry can be beneficial. A holistic policy approach that takes into account the entire supply chain, basic research on technology-specific issues, patents, production processes, resource security and end-user perspectives is essential here. This approach should include SMEs and startups as well as large companies.“ According to the study authors, however, such a holistic approach involves high costs and risks and can therefore only be applied to a limited number of technologies. In this context, systematic and regular screening processes for the selection of key technologies as well as the criteria for a possible termination of funding are particularly important.

The roadmap's team of authors draws the following conclusion: LIBs will continue to dominate the market, but selected alternative battery technologies can ease the dependency on raw materials, production and supply in certain markets and applications and thus contribute to technology sovereignty. However, this will require and merits greater efforts in research and development in Germany as well as in the EU.

The Fraunhofer Institute for Systems and Innovation Research ISI analyzes the origins and impacts of innovations. We research the short- and long-term developments of innovation processes and the impacts of new technologies and services on society. On this basis, we are able to provide our clients from industry, politics and science with recommendations for action and perspectives for key decisions. Our expertise is founded on our scientific competence as well as an interdisciplinary and systemic research approach.