Electromobility Gel filling for lithium-ion batteries improves lifespan

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Researchers at Martin Luther University Halle-Wittenberg (Germany) are developing an innovative gel that could enhance both the safety and efficiency of lithium-ion batteries. This gel aims to replace the flammable liquid electrolytes typically used in these batteries, reducing the risk of leaks and fires. Early laboratory tests suggest that the new material not only mitigates safety concerns but also boosts battery performance and longevity, marking a potential breakthrough in energy storage technology.

Lithium-ion batteries, essential for electromobility, offer faster charging than conventional batteries. However, their electrolyte solutions pose safety risks. As Prof. Dr. Wolfgang Binder, head of the Research Group for Macromolecular Chemistry at Martin-Luther-University Halle-Wittenberg (MLU), explains: “The electrolytes, which transport ions between electrodes to enable electricity flow, are highly flammable, increasing the risk of fire or explosions if damaged.” To address this, MLU researchers are developing a polymer that safely fills the battery cell. This gel-like substance binds the electrolyte but allows ions to move freely between electrodes, offering the high conductivity of liquids with the thermal stability of polymers.This breakthrough could not only improve battery safety but also enhance performance, making electric vehicles more reliable. By combining liquid electrolyte advantages with polymer robustness, MLU’s innovation promises a safer, more efficient energy storage solution that supports the growing demand for sustainable transportation.

Long-term studies necessary

Gel batteries with traditional electrolytes are not fundamentally new; for instance, they are used as starter batteries in motorcycles. However, their application in conjunction with lithium-ion technology is breaking new ground. One major challenge, as Dr. Anja Marinow points out, is that "in existing lithium-ion batteries, the liquid electrolytes form a stabilizing layer on the electrodes during the first charging process that is crucial for the battery's performance and lifespan. For gel electrolytes, however, a fundamentally new design is needed." This challenge was addressed by integrating an ion framework firmly within the polymer's molecular chains. This innovation allows for the formation of a stable, conductive interface between the electrodes and the gel electrolyte, similar to the solid electrolyte interphase (SEI) formed in traditional lithium-ion batteries. This development not only helps maintain the battery's efficiency and longevity but also leverages the inherent safety and thermal stability of gel-based systems. Through this novel approach, researchers are paving the way for safer, more reliable energy storage solutions that could further accelerate the adoption of electric vehicles and other technologies reliant on high-performance batteries.

Initial laboratory tests show that this approach could enhance the safety of batteries and at the same time improve their lifespan and performance. "In conventional lithium-ion cells, approximately 3.6 volts are considered a critical size for the stability of the electrolytes," explains Wolfgang Binder. "Our gel-like electrolytes remain stable even at over five volts." Sustainability is also a key focus of the development: the gels are designed to be relatively straightforward to recycle after a defect or at the end of the battery's life. However, before the new lithium-ion gel batteries can be manufactured on an industrial scale, extensive long-term studies are required. This development represents a promising step forward in battery technology, potentially leading to batteries that are not only safer and more durable but also more environmentally friendly. The ability of these gel-like electrolytes to operate at higher voltages without compromising stability could lead to significant advancements in energy density and efficiency, opening up new possibilities for electric vehicles and other high-demand applications. Additionally, the ease of recycling these gel electrolytes could help mitigate the environmental impact of used batteries, aligning with global sustainability goals.

Further research work

The research was conducted as part of the BAT4EVER project, which was funded under the Horizon 2020 program by the European Commission. The project involved universities, research centers, and industrial partners from Germany, Belgium, Luxembourg, Italy, Spain, and Turkey. Plans are in place to continue and expand the research, particularly in terms of sustainability, within the framework of the "European Center for Just Transition Research and Impact-Driven Transfer (JTC)." The center, which is being established at MLU, aims to develop research-based solutions for structural change in Saxony-Anhalt, such as in the area of circular economy. This initiative not only fosters international collaboration but also directs efforts towards creating technologies that support sustainable development and economic transition in the region.