1. Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), Midorigaoka, Ikeda 563-8577, Osaka, Japan
2. Energy Process Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Onogawa, Tsukuba 305-8569, Ibaraki, Japan
3. Research Institute for Material and Chemical Measurement, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba 305-8565, Ibaraki, Japan
4. The Center for Rare Earths Research, Muroran Institute of Technology, Mizumoto-cho, Muroran 050-8585, Hokkaido, Japan