Advanced Nanoparticle Coatings for Stabilizing Layered Ni-Rich Oxide Cathodes in Solid-State Batteries

Improving the interfacial stability between cathode active material (CAM) and solid electrolyte (SE) is a vital step toward the development of high-performance solid-state batteries (SSBs). One of the challenges plaguing this field is an economical and scalable approach to fabricate high-quality protective coatings on the CAM particles. A new wet-coating strategy based on preformed nanoparticles is presented herein. Nonagglomerated nanoparticles of the coating material (<= 5 nm, exemplified for ZrO2) are prepared by solvothermal synthesis, and after surface functionalization, applied to a layered Ni-rich oxide CAM, LiNi0.85Co0.10Mn0.05O2 (NCM85), producing a uniform surface layer with a unique structure. Remarkably, when used in pelletized SSBs with argyrodite Li6PS5Cl as SE, the coated NCM85 is found to exhibit superior lithium-storage properties (q(dis) approximate to 204 mAh g(NCM85)(-1) at 0.1 C rate and 45 degrees C) and good rate capability. The key to the observed improvement lies in the homogeneity of coating, suppressing interfacial side reactions while simultaneously limiting gas evolution during operation. Moreover, this strategy is proven to have a similar effect in liquid electrolyte-based Li-ion batteries and can potentially be used for the application of other, even more favorable, nanoparticle coatings.

Automated summary

By using preformed nanoparticles synthesized via solvothermal method, a uniform surface layer with unique structure can be formed on layered Ni-rich oxide cathode active material, which contributes to enhanced performance of solid-state batteries.