Applications of In Situ Neutron-Based Techniques in Solid-State Lithium Batteries

Solid-state lithium batteries (SSLBs) have made significant progress in recent decades in response to increasing demands for improved safety and higher energy density. Nonetheless, the current state SSLBs are not suitable for wide commercial applications. The low ionic conductivity, lithium dendrites growth, and unstable interfaces between solid electrodes and electrolytes are some of the challenges that need to be overcome. Therefore, it is critical to fully comprehend the structural information of SSLBs at a nanometer scale. Neutron-based techniques (NBTs) are sensitive to light elements (H, Li, B, N, O, etc.) and can distinguish heavy metals (e.g., Mn, Fe, Co, Ni, etc.) containing close atomic numbers or even isotopes (e.g., H-1 and H-2). Therefore, NBTs are important and powerful structural and analytical tools for SSLB research and have substantially improved our understanding of these processes. To provide real-time monitoring, researchers have explored many sophisticated in situ NBTs to investigate the underlying mechanisms of SSLBs. This minireview article is primarily dedicated to the investigation of SSLBs using in situ NBTs. In addition, it illustrates the capabilities of different in situ NBTs on SSLBs by illustrating the capabilities of different techniques in recently published works. Ultimately, some perspectives for the next evolution of in situ NBTs in SSLBs are highlighted.