Researchers at Osaka Metropolitan University have developed an artificial photosynthesis system that produces formic acid from sunlight, water, and carbon dioxide without using batteries. The key innovation is a self-regulating electrolyzer that adjusts its electrical resistance as it heats up, automatically matching the solar cell's output. This eliminates the need for external maximum power point tracking electronics and batteries, reducing cost and complexity. In outdoor tests, the system produced formic acid steadily even as sunlight fluctuated. The team previously demonstrated the technology at the Osaka Kansai Expo 2025, where it powered a miniature diorama. Formic acid can be used as a fuel or energy storage medium. The research was published in EES Solar.
