Tracking structural dynamics in operando sodium ion batteries*

Sodium ion batteries are promising candidates for storage of energy produced by solar and wind sources. Alternative energy sources are by nature intermittent, and require storage facilities to compensate. Lithium ion batteries, while ubiquitous, are too expensive to satisfy this need. Sodium ion batteries promise to be a cheaper alternative to produce in mass. However, they currently suffer from much faster degradation than Li-ion batteries and often degrade after just a few charge-discharge cycles. Defects in the nanoparticles in lithium ion batteries have been studied by coherent diffraction imaging at X-ray sources (CXDI). We have applied CXDI to sodium ion batteries in operando and obtained information about the evolution of planar and linear defects in the nanoparticles in Na-ion battery cathodes, offering insights in how to improve the performance of Na-ion batteries.