Münster. The demand for lithium-ion batteries (LIB) is growing rapidly. According to a study by the Fraunhofer Institute for Systems and Innovation Research ISI, annual demand is expected to rise to 6,000 GWh per year by 2040. To meet this enormous demand for battery storage capacity or battery cells, not only a large number of battery cell factories are needed, but also a secure, economical and sustainable supply of raw materials. Given the high demand for lithium and the associated supply challenges, the question of alternative battery technologies that do not require lithium is extremely relevant. 

In the search for alternatives, extensive activities in research and industry are particularly evident with regard to sodium-ion batteries (SIB). In these batteries, the rare lithium is replaced by sodium, which is widely available worldwide. Several new industrial players, also known from LIB production, are already producing prototypes or have already started SIB production. According to cell manufacturers, announced global production capacities for SIB cells amount to 75 GWh by 2030.

The newly published environmental report, which was prepared in cooperation with the Fraunhofer Institute for Production Technology IPT, the Chair of PEM at RWTH Aachen University and the Fraunhofer Institute for Systems and Innovation Research ISI, first examines current research activities and related patents and publications in Europe and worldwide. The report then focuses on the characteristics of the industry groups (1) raw material extraction and material development or production, (2) cell development and production, and (3) applications and integration concepts. For each group, current innovations or goals, R&D challenges, and research and industry players in the field are analyzed. The report also shows to what extent Fraunhofer FFB's different innovation paths can support industry in solving R&D challenges at the threshold of industrial applicability of process technologies. The environmental report answers a number of questions regarding the future potential of SIB cells.

How are SIB cells different from LIB cells? 

SIB cells are characterized by good resource availability, safety and deep discharge capability. In terms of materials, sodium is available in Germany in almost unlimited quantities and thus at low cost, e.g. in the form of sodium chloride, i.e. table salt, or sodium carbonate (soda). The higher availability of sodium (compared to lithium) makes it an easily accessible and potentially scalable starting material for energy storage systems. However, sodium does not have the energy density of lithium. This means that the SIB cell can provide less energy than a comparable LIB cell. As a result, research is currently focused on increasing the energy density.

What are the potential applications for SIB cells? 

The range of market forecasts for SIB analyzed in the environment report is very wide. Much of the technological progress has been driven by Asian companies. In the medium term, SIBs will not match the performance of LIBs. However, they can play to their strengths, especially in stationary energy storage and cylindrical battery cells used in small appliances and power tools. “Lithium-ion batteries, which are already on the market, have a much higher energy density on a mass basis, so they can cover a wider range of applications. However, the two technologies are not in competition with each other, but rather serve a strong growth market synergistically. Especially for urban mobility solutions and home storage, sodium-ion batteries can be an attractive solution due to their potentially lower price,” explains Dr. Moritz Schaefer,  researcher at Fraunhofer FFB's Materials Group.

What is the contribution of the European R&D innovation landscape to enable SIB's rapid entry into an economically and strategically independent market? 

In its function as an accelerator unit, Fraunhofer FFB supports industry in solving R&D challenges at the threshold of industrial technology exploitation. For this purpose, German and European industrial partners have access to various innovation paths of Fraunhofer FFB, such as bilateral contract research, participation in funding measures in battery research or industrial scaling in national and European programs. They are designed to help shorten the duration of innovation cycles. 

Dr. Florian Degen, Division Director “Strategy and Corporate Development” at Fraunhofer FFB, points to the need for further funding and expansion of R&D activities to enable entry into an independent European market: “In Germany and Europe, the conditions for the success of sodium-ion batteries are in place. How prices and the supply chain for LIB materials develop in the future will be decisive for the development of an SIB industry. This makes it all the more important to promote cooperation between industry and research, so that German manufacturers can enter the production of sodium-ion batteries at an early stage and use this technology to complement the battery market”.

Background: The "FoFeBat" Project 

The study was conducted as part of the FoFeBat project funded by the German Federal Ministry of Education and Research (BMBF). The goal of the project is to establish the Fraunhofer Research Institution for Battery Cell Production FFB in Münster, a Fraunhofer facility that will enable research and development of battery cell production up to the GWh scale. In particular, the Fraunhofer FFB will take up highly mature technologies (from the prototype stage) and scale them up to industrial applicability.