Lithium-film ceramics for solid-state lithionic devices

The search for alternatives to traditional Li-ion batteries has sparked interest in the chemistry and manufacturing of solid-state Li-ion conductors. Li-ion conductors are traditionally processed as millimetre-sized pellets using conventional ceramic-processing routes. However, in thin-film form, Li-ion conductors offer applications beyond energy storage, including artificial intelligence, in-memory computing and smart sensing. In this Review, we examine the chemistry and thin-film processing of Li oxides and discuss challenges and opportunities for the integration of Li-oxide films in microbatteries for energy storage, neuromorphic computation mimicking human-brain operations and sensors for toxins and greenhouse gases. Li oxides in thin-film form provide fast Li-ion movement and connected electronic-state changes, which improve energy and information density and increase cycle speed and endurance of Li-conductor-based devices. Finally, we provide a future vision of lithionic devices integrating Li-based ceramics for the design of microdevices beyond batteries.