Operando µSR of P2-type Layered Transition Metal Oxides for Sodium Ion Batteries

With its high natural abundance, lower cost and amenable redox potential, sodium ion batteries (SIBs) present a sustainable energy storage alternative to lithium ion. Layered transition metal oxides in the P2 structure show considerable promise as cathodes, where fast Na+ dynamics arise from the low diffusion barrier between adjacent prismatic sites in the Na layer. Here, we propose the first operando study of P2-type Na2/3Ni1/3Mn2/3O2 using the ISIS Battery Analysis by Muon (BAM) cell to investigate the influence of Li on the fundamental Na+ transport mechanism of this promising class of cathodes. Understanding the role of ionic kinetics in these materials is crucial to fine-tune the structural design and cycling protocols to optimize their future electrochemical performance for sustainable energy storage.