A durable P2-type layered oxide cathode with superior low-temperature performance for sodium-ion batteries

Abstract

To power large-scale energy storage systems, sodium-ion batteries (SIBs) must have not only high-energy density but also high performance under a low-temperature (LT) environment. P2-type manganese oxides with high specific capacity are promising cathode candidates for SIBs, but their LT applications are limitedly explored. We proposed a P2-type Na0.67Ni0.1Co0.1Mn0.8O2 material with outstanding LT performance prepared through reasonable structure modulation. The material offers an excellent Na+ diffusion coefficient (approximately 10−9–10−7.5 cm2 s−1) at −20°C, a superior LT discharge capacity of 147.4 mA h g−1 in the Na half-cell system, and outstanding LT full cell performance (energy density of 358.3 W h kg−1). Various characterisations and density function theory calculations results show that the solid solution reaction and pseudocapacitive feature promote the diffusion and desolvation of Na+ from the bulk electrode to interface, finally achieving superior electrochemical performance at LT.