Potassium alloy reference electrodes for potassium-ion batteries: the k-in and k-bi systems

Journal article

Potassium-ion batteries (KIBs) are a promising alternative to conventional lithium-ion batteries with reduced critical mineral dependency but accurate three-electrode characterization is hindered by the lack of a suitable reference electrode. Potassium metal is frequently used as a reference electrode out of necessity, but its high reactivity and unstable potential limit its reliability. Here we investigate the K-In and K-Bi alloy systems, synthesize two-phase In-In4K and Bi-Bi2K alloys, and identify BiBi2K as a promising material owing to its stable potential of 1.07 V vs K+ /K. We prove the use of Bi-Bi2K as a reference electrode by cycling graphite in three-electrode cells and demonstrate that it results in significantly less electrolyte reduction than potassium metal, facilitating the accurate electrochemical characterization necessary to accelerate KIB development.

Authors: Jagger, B; Aspinall, J; Kotakadi, S; Cattermull, J; Dhir, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: ACS Materials Letters
• Volume: 6
• Issue: 10
• Pages: 4498-4506
• Place of publication: United States
• Publication date: 2024-08-30
• Acceptance date: 2024-08-27
• DOI: 10.1021/acsmaterialslett.4c01219
• EISSN: 2639-4979
• Pmid: 39391746
• Language: English