Illustration depicting hydrogen-induced degradation of a sodium-ion battery. Source: Hartwin Peelaers / UC Santa BarbaraSodium-ion batteries, an economical replacement to lithium-ion batteries, historically suffered from premature loss of capacity. Although sodium-ion cells perform well, they have a relatively limited lifespan. In addressing this pitfall researchers at UC Santa Barbara have found that hydrogen-induced degradation is the lead cause of failure.

Professor Van de Walle and his former colleagues at UC Santa Barbara have published their findings in the Chemistry of Materials journal. They found that hydrogen present in the manufacture of a sodium-ion cell is the culprit behind the premature loss of capacity.

A common cathode for a sodium-ion cell, sodium manganese dioxide, was shown to experience a loss of manganese when hydrogen is present. Hydrogen atoms are highly reactive and small, allowing them to penetrate the cathode and mobilize manganese atoms. Results showed that loss of manganese occurred throughout the cathode, that it was irreversible and that it leads to degradation of the battery cell.

With these published findings research can now be focused on suppressing hydrogen during fabrication and encapsulation of sodium ion cells. If sodium-ion batteries can be produced with a comparable lifespan to a lithium-ion battery they can be presented as an economic alternative since sodium is cheap and abundant, while lithium shortages are expected to lead to increased costs and potential shortages.