P3 type layered oxide frameworks: An appealing family of insertion materials for K-ion batteries

K-ion batteries (KIBs) offer an efficient technological alternative to the state-of-the-art Li-ion batteries (LIBs) as energy storage devices with similar chemistry, comparable energy densities, elemental economy and uniformly distributed abundant resources. Nonetheless, their practical implementation warrants robust cathode materials that can yield high gravimetric/volumetric energy density, stable cycle life, and high-rate capability. In this scenario, P3 type layered oxides form an appealing family of KIB cathodes, which includes single transition metal based KxMO2 (M =transition metals) and multiple transition metals based KxMn1-yMyO2. They possess easy and scalable synthesis, high reversible capacity, and adequate operating potential. The current review attempts to capture the most recent advancements in the P3 type KIB cathodes focusing on structural stability, structure-property correlation, and electrochemical performance with suggestions for further material optimization. Finally, the challenges and potential of these P3 type oxide cathodes have been addressed to guide their future research and development as intercalation materials.