Stabilization of single crystal LiNi0.90Mn0.05Co0.05O2 via ZrO2 dual-functional coating enables superior performance for solid-state lithium battery

Chlorine-rich argyrodites with ultrafast Li-ion conductivities exhibits great potential as solid electrolytes for all-solid-state lithium batteries. However, the poor interfacial stability and slow ion dynamics between Li5.5PS4.5Cl1.5 (Cl1.5) and high nickel layered cathode hinder the achievement of superior battery performances. Here, the prepared ZrO2 coating film was found to perform two functions: enhancing the bulk and interfacial stability of single crystal LiNi0.90Mn0.05Co0.05O2 (NCM911) towards sulfide, and facilitating Li-ion transport rates across the interface. A Li2ZrO3 phase with fast Li-ion diffusion rate generates during cycling and further improve the layered-structure integrity of NCM911 and interfacial stability toward the Cl1.5 electrolyte, which are due to the reduction of lattice oxygen release from NCM911 and the isolation of direct contact between the two materials. As a result, these effects enable superior electrochemical performances for the ZrO2-coated NCM911 than the bare sample in Cl1.5-based all-solid-state lithium batteries at varying C-rates and different operating temperatures. It delivers high initial discharge capacities of 156.6 mAh g−1 at 2C and retains 86.0 % of its capacity after 1000 cycles at room temperature, and displays an initial discharge capacity of 172.6 mAh g−1 at 0.5C under 60 °C and 142.4 mAh g−1 at 0.1C under –20 °C, respectively. This dual-functional surface modification strategy provides guidelines to stabilize high-nickel cathode in sulfide-based all-solid-state lithium batteries.