In-operando lithium-ion transport tracking in an all-solid-state battery

Kobayashi, Takane*; Onishi, Tsuyoshi*; Osawa, Takahito  ; Pratt, A.*; Tear, S.*; Shimoda, Susumu*; Baba, Hidetada*; Laitinen, M.*; Sajavaara, T.*

An all-solid-state battery is a secondary battery that is charged and discharged by the transport of lithium ions between positive and negative electrodes. To fully realize the significant benefits of this battery technology, for example, higher energy densities, faster charging times, safer operation, it will be essential to understand how lithium ions are transported and distributed in the battery during operation. However, as the third lightest element, methods for quantitatively analyzing lithium during operation of an all-solid-state device are limited such that real time tracking of lithium transport has not yet been demonstrated. Here, we report that the transport of lithium ions in an all-solid-state half-cell was quantitatively tracked in near real time by utilizing a thermal neutron-induced nuclear reaction, utilizing lithium-6 as a tracer, and utilizing a high-intensity thermal neutron source. Furthermore, it is also mentioned that the migration mechanism and migration region of lithium ions in the solid electrolyte used could be determined by tracking the transport of lithium ions. From these results, it can be said that the development of all-solid-state batteries has entered a phase where further advances could be carried out while understanding the transport of lithium ions in the batteries. As a result, the research and development of all-solid-state batteries would be further accelerated.