Sodium-ion batteries: capturing and reducing defects

Abstract

Sodium superionic conductor (NASICON)-type polyanionic materials are promising cathodes for sodium-ion batteries, but they suffer from voltage hysteresis issues that cause cycling instability. Now, a new type of defect in NASICONs is unravelled as the root cause of voltage hysteresis, and molybdenum doping is shown to decrease defect concentration, improving capacity and cyclability.