Potassium's potential in rechargable batteries

Scientists from Tokyo University of Science have conducted extensive research on potassium-ion batteries (KIBs), finding that the batteries are a better-performing, lower-cost and more sustainable candidate than lithium-ion batteries (LIBs). Replacing lithium in rechargeable batteries with a more abundant material like potassium could result in a more environmentally friendly energy source.

The team’s paper — published in Chemical Reviews — discusses the development of KIBs and compares the different materials used in lithium-, sodium- and potassium-ion batteries.

Rechargeable batteries are used in most portable electronic devices, electric and hybrid vehicles and renewable power-generation systems due to their low-cost, recyclable technology. They are also an essential tool in systems that harvest renewable energy from fluctuating sources such as wind and solar, allowing energy to be stored and dispatched when needed.

LIBs have been the rechargeable battery of choice owing to their excellent performance. However, spikes in demand, coupled with limited availability of lithium and cobalt (another necessary element for LIBs), means that using LIBs may soon become a major problem.

To tackle this challenge, Tokyo researchers led by Professor Shinichi Komaba have focused on replacing lithium with alternatives such as sodium and potassium.

Sodium and potassium are in the same alkali metal group in the periodic table of elements, and their chemical natures are, therefore, quite similar. But, unlike lithium, these elements are widely abundant on Earth, and using them to develop high-performance rechargeable batteries would be a breakthrough towards creating a more sustainable solution.

Demonstrating comparable (or even better) performance to LIBs, KIBs look promising. The materials necessary to build KIBs are non-toxic and much more abundant than those required for LIBs.

“By studying new materials for applications in lithium-, sodium-, potassium-ion batteries, we wanted to develop an energy-efficient and environment-friendly technology,” Prof Komaba said.

“As evidenced by recent intensive research, KIBs are recognised as promising next-generation battery candidates owing to their unique characteristics, such as cost-effectiveness, high voltage and high-power operation.

“Further improvements to the performance of KIBs would pave the way for their practical application,” he explained.

Additional research on the safety of KIBs is needed — the researchers also emphasised that a focus should be placed on exploring what’s going on physically and chemically between the different components and elements.

“Research on KIBs, including electrode materials, non-aqueous/solid electrolytes and additives, will provide new insights into the electrode reactions and solid ionics, opening up new strategies that would allow for the creation of next-generation batteries,” Prof Komaba said.

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