Preparation and electrochemical properties of LiAlO2-coated Li(Ni1/3Mn1/3Co1/3)O2 for all-solid-state batteries

• LiAlO2 coating was performed on LiNi1/3Mn1/3Co1/3O2 powders by sol–gel methods.
• All-solid state lithium battery was fabricated with the LiAlO2-coated LiNi1/3Mn1/3Co1/3O2.
• The battery showed discharge capacity of 134 mAhg −1 under a current 11 mAg- 1 at 25 °C.
• The battery kept the capacity larger than 124 mAhg −1 even after 400 cycles.

LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 powders were prepared by a sol–gel method associated with ultra-sonication, and the obtained LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 was investigated as positive electrode materials for all-solid-state batteries with sulfide-based solid electrolytes. All-solid-state lithium batteries were assembled with the obtained LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 powders and with amorphous Li3PS4 as solid electrolytes. The charge–discharge cycle performance of the all-solid-state cells was improved by the LiAlO2-coating on LiNi1/3Mn1/3Co1/3O2 powders. The LiAlO2 coating was effective in suppressing an increasing of the interfacial resistance between the LiNi1/3Mn1/3Co1/3O2 electrode material and the sulfide based solid electrolyte, Li3PS4, during charge–discharge cycling. The battery with the 1.0 mol% LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 showed an initial discharge capacity of 134 mAhg− 1 and the battery retained the capacity more than 124 mAhg −1 even after 400 charge–discharge cycles at a current density of 11 mAg −1 at room temperature.