© Ulrike Wunderwald / Fraunhofer IISB

Aluminum-ion batteries as an alternative storage technology for stationary applications

In the ALBATROS project, a consortium from research and industry is further developing the aluminium-ion battery (AIB). The focus is on the processes in the battery cell and at the interfaces between electrodes and electrolyte. Aluminum-ion batteries have a high potential in terms of safety, cycle stability and charge rate. Aluminum-ion technology also offers advantages in terms of production costs, raw material availability and recycling. Consortium partners in the ALBATROS battery project are Fraunhofer IISB, IoLiTec GmbH, DECHEMA Research Institute and the Institute of Inorganic Chemistry at the Technical University Bergakademie Freiberg.

The consortium in the ALBATROS project is focusing on a substantial further development of the aluminium-ion battery. The acronym stands for “Alternative material systems for stationary battery storage based on aluminium as anode material for the substitution of critical raw materials”. The aim of the project is to create a comprehensive basic understanding of the processes in the battery cell and in particular at the interfaces between electrodes and electrolyte. The novel aluminum-based cell chemistry has promising potential in terms of safety, cycle stability and charge rate. Particularly relevant here is the avoidance of critical raw materials, such as lithium, nickel or cobalt. Within the ALBATROS project, Fraunhofer IISB (Erlangen / Freiberg), IoLiTec GmbH (Heilbronn), the DECHEMA Research Institute (DFI, Frankfurt am Main) and the Institute of Inorganic Chemistry at the Technical University Bergakademie Freiberg are working together. The ALBATROS project is funded by the Federal Ministry of Education and Research (BMBF).

A significant increase in demand is forecast for stationary electrical storage. It can already be seen today that this strong growth cannot be covered by conventional battery technologies. Particularly with regard to the critical raw materials used to date and the costs of battery storage, alternatives to the established cell chemistries are needed in the near future. One promising option is the aluminum-ion battery (AIB). The first functional samples have already been presented at the Technology Center for High Performance Materials (THM) of Fraunhofer IISB in Freiberg (see info links).

Compared to lead-acid or Li-ion batteries, aluminum-ion technology offers significant advantages, especially in terms of manufacturing costs and raw material availability. But also in terms of hazard potential and recyclability, aluminium-ion batteries can be a thoroughly convincing alternative due to the use of non-flammable electrolytes.
Inexpensive aluminium and graphite can be used as electrode materials for the AIB. The electrolytes are based on so-called ionic liquids and, in interaction with the other materials, make the reversible charging process of the aluminium-ion battery possible in the first place. With the very high cycle stability of more than 20,000 cycles and charge rates of more than 150 C, further developed aluminium-graphite systems hold enormous potential for future applications. The non-flammability of the components and the electrolyte makes the AIB a safe storage option, for example for electricity from fluctuating renewable energy sources.

However, further scientific preliminary work is required before the AIB can be launched on the market. A particular challenge here is the highly corrosive behaviour of the electrolytes previously used in AIB. Before application-relevant prototype cells are available for testing, extensive material qualification, testing and certification must be carried out. For the theoretical foundation of the novel cell chemistry, the scientists concentrate on the basic chemical mechanisms and material-specific influencing variables. Among other things, the kinetic parameters of aluminium dissolution and deposition on the aluminium anode are investigated for different electrolyte compositions. Likewise, the focus is on the input and output of charge carriers into and out of the graphite matrix. This also includes specific analyses of the species of the charge carriers. Another focus is the investigation of self-discharge processes. This effect is of particular interest for later applications.

The knowledge gained is the indispensable basis for the design, further development and optimisation of application-oriented and sustainable AIB storage systems. Here, as a realistic first step, an application in stationary electrical storage systems is aimed at. Thus, the aluminum-ion battery can be an essential building block for the expansion of urgently needed storage capacities and contribute to the success of the energy transition. The ALBATROS project makes elementary contributions to the realization of efficient, durable, cost-effective, environmentally compatible and easily recyclable battery components.

The ALBATROS project is funded by the Federal Ministry of Education and Research (BMBF).

Fraunhofer THM

The Fraunhofer Technology Center for High Performance Materials THM is a research and transfer platform of the Fraunhofer Institute for Integrated Systems and Device Technology IISB and the Fraunhofer Institute for Ceramic Technologies and Systems IKTS. Within the framework of industrial orders and publicly funded projects, semiconductor and energy materials are jointly transferred into new applications, with special consideration of future material recycling. One focus of the work at Fraunhofer THM is the analysis and development of sustainable battery systems with improved life cycle assessment and raw material availability compared to established battery technologies.

Fraunhofer IISB

Intelligent power electronic systems and technologies – this is the motto under which the Fraunhofer Institute for Integrated Systems and Device Technology IISB, founded in 1985, conducts applied research and development for the direct benefit of industry and society. With scientific expertise and comprehensive systems know-how, it supports customers and partners worldwide in translating current research results into competitive products, for example for electric vehicles, aviation, production and energy supply.

The institute bundles its activities in the two business units Power Electronic Systems and Semiconductors. In doing so, it comprehensively covers the entire value chain from basic materials to semiconductor component, process and module technologies to complete electronics and energy systems. As a unique European competence center for the semiconductor material silicon carbide (SiC), IISB is a pioneer in the development of highly efficient power electronics, even for extreme requirements. With its systems, IISB repeatedly sets benchmarks in energy efficiency and performance. Through the integration of intelligent data-based functionalities, new application scenarios are continuously being developed.

IISB has around 300 employees. The main location is in Erlangen, another location is at the Fraunhofer Technology Center for High Performance Materials (THM) in Freiberg. The institute cooperates closely with the Friedrich-Alexander-University Erlangen-Nuremberg (FAU) and is a founding member of the Energy Campus Nuremberg (EnCN) as well as the Performance Center Electronic Systems (LZE). IISB cooperates with numerous national and international partners in joint projects and associations.