Enhanced ion-electron mixing interface for high energy solid-state lithium metal batteries

Solid-state Li metal batteries (SSLMBs) are famous for superior security and excellent energy density. Nevertheless, the poor interfacial contact between solid lithium and electrode is one key problem in the development of SSLMBs, resulting in high impedance and growth of lithium dendrites along the grain boundaries. Herein, an innovative and accessible approach has been applied to SSLMBs, which introduces an ion-electron mixing (IEM) interface on the surface of Li1.3Al0.3Ti1.7(PO4)3 (LATP). The IEM interlayer generates LixSn/LiI of fast lithium-ion conductor through an in-situ reaction. The existence of LiI would promote the quick transmission of Li+ at the interface and inhibit the electronic conduction, thus restraining the growth of lithium dendrites. The batteries with IEM@LATP electrolyte could stably cycle more than 1000 h at high current density of 0.1 mA cm-2. Even increasing the current density to 3.0 mA cm-2, the batteries still could work normally. This novel and viable approach offers a robust basis for the practical application of SSLMBs and has some general applicability to other solid-state batteries.