Innovative battery electrode made from tin foam
Metal-based electrodes in lithium-ion batteries promise significantly higher capacities than conventional graphite electrodes. Unfortunately, they degrade due to mechanical stresses during charging and discharging cycles. A team at HZB has now shown that a highly porous tin foam can significantly better absorb the mechanical stress during charging cycles. This makes tin foams an interesting potential material for lithium batteries.
Modern lithium-ion batteries generally rely on a multi-layer graphite electrode, while the counter electrode is often made of cobalt oxide. During charging and discharging, lithium ions migrate into the graphite without causing significant volume changes in the material. However, the capacity of graphite is limited, making the search for alternative materials an exciting field of research. Metal-based electrodes, for example made of aluminum or tin, potentially offer a higher capacity. However, they tend to expand significantly in volume when absorbing lithium, which is associated with structural changes and material fatigue.
One option for realizing metal electrodes that "fatigue" less quickly is to nanostructure the thin metal foils. Another option is the use of porous metal foams. Tin is a particularly attractive metal because it has almost three times the capacity per kilogram of graphite and is also not a rare raw material but is available in abundance.
A research team from the Helmholtz-Zentrum Berlin (HZB) has now investigated different types of tin electrodes during the discharging and charging process using operando X-ray imaging and developed an innovative approach to tackle this problem. Part of these investigations took place at the BAMline at BESSY II. In addition, high-resolution radioscopic X-ray images were taken in collaboration with imaging experts Dr. Nikolai Kardjilov and Dr. André Hilger at HZB. "In this way, we were able to follow the structural changes in the Sn-metal-based electrodes under investigation during the charging/discharging processes," says Dr. Bouchra Bouabadi, who conducted the experimental study. In collaboration with battery expert Dr. Sebastian Risse, she shows how the morphology of the tin electrodes changes during operation due to the inhomogeneous absorption of lithium ions.
Dr. Francisco Garcia-Moreno produced the best version of the tin electrode: A foam made of tin with countless micrometer-sized pores. "We were able to show that significantly less mechanical stress occurs in such a tin foam during volume expansion," says Dr. Risse. This makes tin foams an interesting potential material for lithium batteries.
Garcia-Moreno has already investigated numerous metal foams, including those for components in the automotive industry and aluminum foams for battery electrodes. "The tin foams we developed at TU Berlin are highly porous and an interesting alternative to traditional electrode materials," he says. The structuring of tin foams is crucial in order to reduce mechanical stress as much as possible. Tin foam technology could also be interesting from an economic point of view: "Although tin foam is more expensive than conventional tin foils, it offers a more cost-effective alternative to expensive nanostructuring, while at the same time it can store significantly more lithium ions and thus enable an increase in capacity."
Note: This article has been translated using a computer system without human intervention. LUMITOS offers these automatic translations to present a wider range of current news. Since this article has been translated with automatic translation, it is possible that it contains errors in vocabulary, syntax or grammar. The original article in German can be found here.
Original publication
Bouchra Bouabadi, André Hilger, Paul H. Kamm, Tillmann R. Neu, Nikolay Kardjilov, Michael Sintschuk, Henning Markötter, Thomas Schedel‐Niedrig, Daniel Abou‐Ras, Francisco García‐Moreno, Sebastian Risse; "Morphological Evolution of Sn‐Metal‐Based Anodes for Lithium‐Ion Batteries Using Operando X‐Ray Imaging"; Advanced Science, 2025-1-17
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