Application of <i>in</i>-<i>situ</i> characterization techniques in all-solid-state lithium batteries

In recent years, mobile consumer electronics and electric vehicles have been developing rapidly, and they have been hunting for lithium batteries with high energy density, high safety and stability, to alleviate the range anxiety and improve their stability over long term operations. These make all-solid-state lithium batteries very attractive and they have been under intense investigations. However, the development of high-performance all-solid-state lithium batteries requires an in-depth understanding of their charge and discharge mechanism, their degradation process, along with the evolution of the microstructures, phase compositions, chemical states and their distributions, etc., inside the battery and at the interface. This paper summarizes the basic principles, functions, and the representative advances in investigation of the dynamics and failure mechanism of electrode materials and interfaces in solid-state lithium batteries under working conditions, with typical <i>in-situ</i> characterization techniques, including in-situ microscopy (in-situ scanning electron microscopy (SEM), in-situ transmission electron microscopy (TEM)), in-situ X-ray techniques (<i>in-situ</i> X-ray diffraction (XRD)), in-situ X-ray photoelectron spectroscopy (XPS), <i>in-situ</i> near-edge structure X-ray absorption spectroscopy (XANES), <i>in-situ</i> X-ray tomography), <i>in-situ</i> neutron techniques (<i>in-situ</i> neutron diffraction (ND), <i>in-situ</i> neutron depth profiling (NDP)) and <i>in-situ</i> spectroscopies (<i>in-situ</i> Raman spectroscopy, <i>in-situ</i> nuclear magnetic resonance (NMR) and <i>in-situ</i> nuclear magnetic resonance imaging (MRI)), etc. We also discussed the application of future advanced in-situ characterization techniques in the investigation of all-solid-state lithium batteries.