Two coffee/caffeine/electricity-generation studies to consider:
“Direct power generation from waste coffee grounds in a biomass fuel cell,” Hansaem Jang, Joey D. Ocon, Seunghwa Lee, Jae Kwang Lee, and Jaeyoung Lee, Journal of Power Sources, 296 (2015): 433-439.
“Caffeine Improves the Performance and Thermal Stability of Perovskite Solar Cells,” Rui Wang, Jingjing Xue, Lei Meng, Yonghai Yuan, Yu Huang, and Yang Yang, Joule, April 25, 2019.