1. Department of Chemical Engineering Stanford University Stanford CA 94305 USA
2. Products Development Department Sony Corporation 1‐1 Shimosugishita Takakura Hiwada‐machi Koriyama‐shi Fukushima 963‐0531 Japan
3. Department of Materials Science and Engineering Stanford University Stanford CA 94305 USA
4. Stanford Institute for Materials and Energy Sciences SLAC National Accelerator Laboratory Menlo Park CA 94205 USA