Osaka researchers develop battery-free artificial photosynthesis for cheaper solar fuel production

Researchers at Osaka Metropolitan University have built an artificial photosynthesis system that removes the need for batteries and external control electronics. The device uses a solid electrolyte inside the electrolyzer to self-regulate power flow as sunlight changes, keeping formic acid production stable without the costly Maximum Power Point Tracking hardware normally required. The system naturally heats up under stronger sunlight, lowering its electrical resistance and allowing more current to flow. This automatic adjustment keeps fuel output steady even when clouds pass by. The team demonstrated the technology at the Osaka Kansai Expo 2025, where it powered a small diorama. If scaled, this approach could lower the cost of producing solar fuels for home or industrial use. The research was published in EES Solar and represents a practical step toward cheaper, simpler artificial photosynthesis systems that directly convert CO2 into storable energy.