Ionic conductivity of metal oxides : an essential property for all-solid-state Lithium-ion batteries

Essential progress has been made for adopting metal oxides (MeO) in various energy storage and energy conversion applications. Among these, utilizing MeO in Lithium-ions batteries (LIBs) seems to be one of the most promising applications. In particular, conductive Li-containing oxides or mixed-oxides materials, used as solid electrolytes, can pave the way to construct all-solid-state LIBs. In contrast to conventional LIBs, in which a liquid electrolyte and a separator are necessary in the configuration shown in Figure 1a, these can be replaced in all-solid-state LIBs by a single layer of solid-state electrolyte (see Figure 1b). As a result the restrictions, regarding the design and size of liquid-based LIBs are much more reduced in all-solid-state batteries, which will further facilitate future miniaturization of small-sized electronics. Furthermore, avoiding liquid organic electrolytes will offer a much better safety to electronic systems, especially for medical implants.[1] Moreover, MeO are promising high performance electrode materials and have already been widely applied in both scientific and industrial fields due to the high theoretical capacity, natural abundance and cost-effective properties, owning to the widespread natural availability of these minerals. Therefore, it is of great importance, benefit and advantage to build all-solid-state LIBs by making use of MeO. In this chapter, attention will be focused on thin film-based all-solid-state LIBs.