Potassium metal batteries (PMBs) are gaining attention as a cost-effective alternative to lithium-ion batteries, thanks to potassium's abundance and similar chemical properties. However, issues like uncontrolled dendrite growth and interfacial instability undermine the performance and safety of PMBs, posing a major challenge that demands new solutions to stabilize the anode interface and prevent dendrite formation.

Researchers from Northeastern University and their collaborators published their findings in the journal eScience. Their study, "Realizing a Dendrite-Free Metallic-Potassium Anode Using Reactive Prewetting Chemistry," introduces a novel approach to constructing a KF/Zn-rich hybrid interface layer on potassium metal.

This interface enhances ion and electron transport dynamics, resulting in an anode with improved electrochemical performance and prolonged stability over 2,000 hours of cycling.

The team developed a KF/Zn hybrid interface layer on potassium metal anodes using a reactive prewetting technique that boosts battery stability and efficiency. Potassium fluoride (KF) serves as a robust electron tunneling barrier that curbs dendrite growth, while zinc (Zn) nanocrystals enhance electrical conductivity and ion transport. This dual-layer interface stabilizes the anode, facilitating seamless ion and electron flow crucial for long-term battery performance.

The study demonstrated that batteries featuring the KF/Zn@K anode sustained more than 2,000 hours of stable cycling with minimal voltage fluctuation and remained dendrite-free. Full battery cells using this anode also exhibited a high reversible capacity of 61.6 mAh/g at 5 C for more than 3,000 cycles, marking a significant step towards safer, high-performance potassium metal batteries for large-scale energy storage.

"Our research offers a straightforward yet effective solution to the persistent issue of dendrite growth in potassium metal batteries," said Dr. Wen-Bin Luo, lead researcher. "By designing a hybrid interface layer that balances ion and electron transport, we not only enhance battery performance but also significantly improve safety, making PMBs more viable for widespread energy storage applications."

The advent of a dendrite-free potassium metal anode presents new opportunities for safer and more dependable PMBs, which could be pivotal for large-scale energy storage systems. This breakthrough addresses critical safety challenges and offers a scalable approach to boost the energy density and lifespan of future batteries, potentially revolutionizing the field of renewable energy storage technologies.

More information: Lu-Kang Zhao et al, Realizing a dendrite-free metallic-potassium anode using reactive prewetting chemistry, eScience (2023). DOI: 10.1016/j.esci.2023.100201

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