The use of renewable energy is indispensable for the realization of a low-carbon society. Storage and regular use of electricity by solar and wind power generation are required. Redox flow batteries (RFBs) are expected to be a stationary power source because RFBs are suitable for long-term operation and large-scale storage. Although V-based RFBs are in practical use, Ti-Mn-based RFBs are also being developed from the viewpoint of energy density and cost.

In the development of Ti-Mn based RFBs, it is important to improve the stability of the cathode electrolyte for suppression of precipitation of oxidized Mn ions by charging. Since the formation of precipitates leads to decreasing of energy density, this problem needs to be solved. Firstly, it is important to elucidate the mechanism. However, the detailed electronic states of transition metal ions in the electrolyte and precipitates have not been clarified. In this presentation, we report a detailed analysis of the electrolyte and precipitates by synchrotron soft X-ray absorption spectroscopy.1

Reference

1) Asakura, D.; Hosono, E.; Kitamura, M.; Horiba, K.; Magome, E.; Setoyama, H.; Kobayashi, E.; Yuzawa, H.; Ohigashi, T.; Sakai, T.; Kanega, R.; Funaki, T.; Sato, Y.; Ohira, A., Redox Reaction in Ti-Mn Redox Flow Battery Studied by X-ray Absorption Spectroscopy, Chem. Asian J. 2023, 18, e202201047.