On the synthesis and potential benefit of Na-rich P-type layered oxides for high power Na-ion batteries

Layered oxides with the general composition NaxMO2 (M = transition metal) have attracted a lot of attention for their composition diversity and promising electrochemical performances as positive electrode for sodium-ion batteries. P-type compositions offer power capabilities owing to the fast diffusion of sodium cations but are plagued by limited specific capacities because of the nominal low amount of sodium in the structure. Therefore, sodium enriching of P-type structure is consequently of interest to propose electrode candidates combining high energy density and high power capabilities.