[1Ga01-10] Thin Film (TF)

[1Ga07] Low-potential-application-induced activity recovery observed in LiNi_0.5Mn_1.5O₄(111) thin film catalysts for oxygen evolution reaction

*Kentaro Hatagami¹, Kazunori Nishio¹, Ryota Shimizu², Taro Hitosugi^1,2 (1. Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 2. Department of Chemistry, School of Science, University of Tokyo)

Cathode materials in Li-ion secondary batteries have attracted much attention as oxygen evolution reaction (OER) catalysts in water splitting. In this study, we focused on LiNi_0.5Mn_1.5O₄ (LNMO) among the cathode materials. We utilized LNMO(111)/Au(111)/Al₂O₃(0001) oriented thin films to define the reaction area. OER was performed on the LNMO(111) thin film by sweeping the potential to +2.0 V vs. reversible hydrogen electrode (RHE) (pH 13.0). While a current density of 15.7 mAcm^-2 was obtained in the first cycle, the current density decreased to 6.70 mAcm^-2 in the eighth cycle, suggesting the degradation of OER activity. Surprisingly, we found that the OER activity was recovered to 16.5 mAcm^-2 by applying a low-potential to -0.8 V vs. RHE, and then re-sweeping to +2.0 V vs. RHE.