Tokyo Researchers Find Key to Boosting Sodium-Ion Battery Cycle Life

Scientists at Tokyo University of Science have developed a new technique that could significantly improve the commercial viability of sodium-ion batteries, positioning them as a strong alternative to lithium-ion cells.

A research team led by Professor Shinichi Komaba has found that doping sodium manganese oxide cathodes with scandium enhances their structural stability, allowing batteries to retain performance over longer cycles. In lab tests, scandium-doped electrodes maintained around 60% capacity after 300 cycles, compared with rapid degradation in non-doped samples.

Attracting Global Attention 

Sodium-ion batteries have been attracting global attention as a cheaper, more abundant substitute for lithium-ion technology, particularly for stationary storage and grid-scale applications. While sodium is plentiful, the main drawback has been poor cycle life caused by structural distortions in cathode materials.

The Tokyo study, published in Advanced Materials, shows that scandium doping reduces these distortions in the P’2 polytype of Na₂/₃MnO₂, helping preserve crystallinity and resist side reactions with electrolytes. Interestingly, the improvement was unique to the P’2 type and not observed in the P2 variant or with other metals like aluminium or ytterbium.

Expensive Element 

“Scandium is an expensive element, but our work demonstrates its potential to unlock long-life sodium-ion batteries,” said Prof. Komaba. “The findings also suggest new design strategies for layered metal oxides beyond sodium systems.”

The research underscores growing momentum in sodium-ion development at a time when lithium supply faces price and geopolitical pressures. Global battery makers including CATL and Reliance New Energy have already been exploring sodium-based chemistries to diversify supply chains.

Funding for the project came from Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT), JST CREST, ASPIRE and JSPS KAKENHI.