Garnet solid electrolyte blended LiNi0.6Mn0.2Co0.2O2 as high-voltage stable cathodes for advanced lithium-ion batteries

Ni-rich LiNi1-xCox/2Mnx/2O2 layered materials have been widely adopted as cathodes for current electric vehicles (EVs) due to their high gravimetric and volumetric energy densities. However, their high-voltage instability (e.g., > 4.3 VvsLi) limited their usable capacities corresponding to about 60 – 70 % of theoretical capacities. The major problems of high-voltage operation stem from instability of Ni3+/4+ at cathode-electrolyte interphase (CEI) in contact with electrolytes. Here we propose garnet-type Li6.7La3Zr1.7Ta0.3O12 (LLZT) solid-electrolyte-blended LiNi0.6Mn0.2Co0.2O2 (NMC) as high-voltage stable cathodes. The LLZT not only passivates the CEI but scavenges protons and moisture in electrolytes. From well-balanced ionic and electronic transport properties, 5 wt% LLZT blended NMC cathodes delivered enhanced electrochemical performances in full-cells. Unlike other complicated coating processes, our proposed solid-electrolyte blending approach can be readily implementable in commercial Li-ion batteries due to its manufacturing friendliness, energy saving, and cost effectiveness.