Nanotechnology in solid state batteries, what’s next?

High-safety solid state batteries (SSBs) have been considered as the most potential candidate energy storage devices for supporting energy Internet. However, their large-scale application is suffering from challenges such as severe interface failure. Nanotechnology has been used to study and address the above problems due to small scale-induced unique physical-chemical properties. Herein, this review systematically elaborates the application of nanotechnology in key materials (cathode, solid-state electrolyte (SSE), anode) of SSBs, and emphasizes its role in enhancing structural stability and lithium-ion transport dynamics of electrodes, SSEs, and the interfaces between them. Then, the preparation methods of nanomaterials for SSBs are also summarized and evaluated. Lastly, we deliver the prospect on how to tactfully introduce nanotechnology to develop the high-energy and long-life SSBs. This review provides valuable guidance for understanding the function of nanotechnology in solving the bottleneck of SSBs, and exploring how to broaden its application in the next energy materials.