Researchers says “doping” with calcium could solve sodium-ion battery stability issues

Japanese researchers are laying claim to a technology breakthrough that could help solve some of the barriers to the development of potentially low cost and longer lasting sodium-ion batteries.

The researchers from the Tokyo University of Science (TUS) have proposed using so-called calcium doping to improve the stability of sodium-ion batteries, long hailed as an important rival to lithium-ion technologies.

However, adoption of sodium ion batteries has been restricted by the technology’s poor stability in air and water, specifically that of its cathode material, which can in turn degrade the battery’s performance and lifespan.

The TUS researchers say they have demonstrated that calcium doping can prevent the degradation of SIB cathode materials in both air and water.

Solving the stability issue of sodium-ion battery technology could be a significant game-changer, as it would transition the reliance from scarce lithium resources to abundant sodium.

The potential solution focuses on enhancing the air and water stability (NFM), which the researchers said they could do by replacing some of the sodium (Na) ions with calcium (Ca) ions – a technique known as ‘doping’.

“This newly explored mechanism appears to be quite effective for mitigating surface degradation reactions in layered oxides,” said Shinichi Komaba, a professor at TUS.

The research team also found that calcium doping improved the crystallinity and increased interlayer spacing in NFM, contributing to a better electrochemical performance and also shielding the NFM during storage before battery assembly.

The apparent protective effects of calcium doping in NFM could potentially pave the way for widespread adoption of sodium-ion batteries with little cost impact on manufacturing, considering that calcium materials are abundantly available and can be easily incorporated into NFM using synthetic techniques.

This would also substantially benefit renewable energy generation by providing a more sustainable and cost-effective solution for large-scale storage, while also addressing increasing lithium scarcity issues.