Identified challenges in lithium-sulphur batteries with minimal electrolyte content

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Researchers at the Helmholtz-Zentrum Berlin (HZB) are making strides in the development of compact lithium-sulfur (Li-S) batteries with high energy density. The focus of their work is on understanding electrolyte distribution and battery failure mechanisms, using advanced neutron tomography methods.

One of the key findings by Prof. Dr. Yan Lu and his team is the significance of homogeneity in the electrolyte during charge/discharge cycles. This homogeneity promotes the electrochemical activation of sulfur, a more abundant element than critical metals like cobalt and nickel used in lithium-ion batteries.

The team's efforts have resulted in the production of multi-layered Li-S pouch cells with reduced electrolyte, adhering to industrially relevant parameters. However, incomplete wetting of electrodes in Li-S batteries can disrupt electrochemical processes, leading to faster aging or failure.

In their study, the researchers observed periodic processes in electrolyte wetting that correlate with the dissolution and precipitation of sulfur compounds. During the battery's idle phase at open-circuit voltage, dry spots were particularly prevalent initially in local areas.

To investigate these issues, Dr. Ingo Manke and Dr. Nikolay Kardjilov from HZB's imaging group examined these samples using neutrons to locate light elements like lithium and hydrogen. Their findings provide valuable insights into the dynamics of electrolyte wetting in Li-S battery systems.

Reducing the amount of electrolyte in Li-S batteries is crucial for increasing energy density. Li-S batteries have a gravimetric energy density over 700 Wh/kg, higher than modern Li-ion batteries. This high energy density makes Li-S batteries an attractive option for various applications, including electric vehicles and grid storage.

The HZB research teams' work continues to contribute to the development and understanding of Li-S battery technology, with the ultimate goal of creating more efficient and reliable energy storage solutions for the future.

Identified challenges in lithium-sulphur batteries with minimal electrolyte content