Title: Dynamics of lithium around electrode/solidelectrolyte interface in all solid-state batteriesunder charging and discharging by ion beam analysis

Abstract

Anoxide-based solid-state rechargeable lithium ion (Li+) batterie is one of the most remarkable next genertion devices. To realize the product, it is essential that we have information on the Li+ ion transfer resistance at electrode/solid electrolyte interfaces and grain boundaries in the solid-state Li+ ion batteries. In particule, the Li deficient region formed around the interface during the charging and discharging, which is indicative of space charge layer, locally provides less Li+ ionconduction and then leads to the interfacial Li+ ion transfer resistance, since the Li+ionic conductivity in the solid electrolyte significantly depends on the number of Li+ ion mobile carriers. Thus, the Li distribution around interface in static or operated solid-state Li+ ion batteries should be clarified well. In the study, we have in situ investigated the static Li distributions around each LiCoO2 positive electrode/Li1+xAlxGe y Ti2-x-yP3O12– AlPO4(LATP) electrolyte and LiMn2O4 positive electrode/Li3.3PO3.8N0.2(LiPON) electrolyte/ Nb2O5 negative electrode interface in Au/ LiCoO2/LATP/Pt and Ti/LiMn2O4/LiPON/Nb2O5/ Ti batteries with charging and discharging by combined ion beam analysis of high-energy elastic recoil detection (ERD) and Rutherford backscattering spectrometry (RBS)techniques using 9.0MeV oxygen ion (O4+) and 5.0MeV heliumion (He2+) probe beams from a tandem accelerator. The ERD spectra with reliable depth resolution in a few tens of nm scale revealed the that the Li concentration in the positive (negative) electrode uniformly decreased (increased) at several depths with increasing the applied voltages and the Lidepletion region was formed inside the solid electrolyte at the interface with the thickness of approximately 120 ± 30 nm.

Biography

Bun Tsuchiya is a professor at Meijo University. He belongs to Japan.He completed his doctor’s degree in materials science from Nagoya University, Nagoya city. He joined the Institute for Materials Research in Tohoku university as assistant professor in April 1998 and the Faculty of Science and Technology in Meijo University as associate professor in April 2010 and as professor in April 2017. He has many international research contributions on the energy materials related to nuclear fusion, fuel cell, and lithium ion battery. His major interest is to investigate the behaviors of some elements with low atomic numbers such as hydrogen, helium, and lithium, and so on in the many different kinds of materials such as metals, semiconductors, and insulators using ion beam analysis. His recent project is to clarify the migration of lithium ions at the interface between the positive- and negative-electrodes and solid-electrolytes in the all-solid-state lithium batteries by charging and discharging using combined elastic recoil detection with Rutherford backscattering spectrometry techniques.