P2/P3 composite layered cathode materials for sodium ion batteries

Sodium-ion batteries (NIBs) are a more sustainable, cheaper and safer energy storage solution to lithium-ion batteries (LIBs). The best performing NIBs contain sodium layered oxide cathode materials, based around sodium, nickel and manganese, which typically adopt one of three structures P2,P3 (with trigonal prismatic sodium and O3 (with octahedral sodium). Recent studies have demonstrated that materials comprising nanoscale intergrowths of different phases can result in superior properties compared to single-phase equivalents. We have prepared a series of P2/P3 composites with excellent cycling performance and high voltages that are competitive with current commercial materials. This experiemnt seeks to understand the transition metal distribution in the component phases and the structural evolution on charge/discharge.