Led by chemists from Glasgow University and battery testing experts at Helmholtz Institute Ulm, the research brings potassium-ion batteries a step closer to becoming a viable alternative to lithium-ion systems. According to the team, this is due to the abundant availability of potassium and its advantageous material properties like rapid charging.
Experts believe that the batteries could be cheaper and easier to manufacture in the future than lithium-ion batteries, opening up applications including the storage of electricity generated from renewable sources.
Dr Alexey Ganin, of Glasgow University’s School of Chemistry, is the paper’s lead author and the head of the Glasgow ElectroChemistry on Solids (GECOS) group.
“Lithium-ion batteries have become widely adopted in devices from smartphones to electric cars in recent years, and are capable of excellent performance, but lithium is a relatively rare, and therefore strategically important, element,” he said in a statement. “Potassium is a much more abundant material, and potassium-ion batteries have a lot of potential as an alternative method of storing and delivering large amounts of electricity. Adopting potassium-ion batteries for stationary storage purposes could help free up lithium resources for use in more energy-intensive mobile applications in the future.”
Some of the best-performing current designs for potassium-ion batteries use cathodes made from Prussian White but their design is said to be complicated by the need to mix the material with carbon to boost its conductivity and deliver the best results.
In a paper published in the Journal of Materials Chemistry A, the researchers show how their naturally conductive chromium selenide cathode achieves high performance with less than 10 per cent carbon. Their prototype has a capacity of 125mAh/g (milliamp-hours per gram), very close to its maximum theoretical capacity of 127 mAh/g.
The layered nature of the material allows potassium ions to travel more easily between the layers during charge and discharge, allowing the battery to maintain 85 per cent of its capacity in lab conditions even when charged and discharged at high speed.
The next step for the team is further research to identify an electrolyte which will help deliver improved performance in future refinements of the battery’s design.
Dr Ganin said: “These are promising results, but we believe the performance of the battery could be boosted further with the right electrolyte. Designer lithium-ion battery electrolytes can be bought off the shelf, but further work is required to refine the performance of electrolytes for potassium-ion batteries. We’re keen to partner with robotics experts who can help us test the thousands of potential chemical combinations to find the best possible candidate for use in our battery.”
Researchers from Ulm University, the Karlsruhe Institute of Technology, the Kent University, the Catalan Institute of Nanoscience and Nanotechnology, and ICREA also contributed to the paper.
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I'd like to know where these are operating in the UK. The report is notably light on this. I wonder why?