From Li${}_2$NiO${}_3$ to high-performance LiNiO${}_2$ cathodes for application in Li-ion and all-solid-state batteries

The synthesis of LiNiO${}_2$ (LNO) typically involves oxidizing Ni(II) to Ni(III), thus leading to Ni${}_{Li}$ point-defect formation. Here, materials containing Ni(IV) in the form of overlithiated Li${}_{1+x}$Ni${}_{1-x}$O${}_2$ (0 ≤ x ≤ 1/3) are converted into LNO. This method produces low defect-density samples at high temperatures, offering an attractive route toward coarse-grained particles that are naturally coated by the byproduct Li${}_2$O. In thiophosphate-based solid-state batteries, this kind of self-coating effect shows a direct correlation between residual lithium content and cycling performance.