Traditional thermal batteries rely on high-temperature gases or molten salts circulated through metal pipes, vulnerable to corrosion and fatigue. Fourth Power inverted this model by using molten metal as the heat transfer medium and carbon bricks as storage units, enhancing durability and thermal management. This system enables energy storage at white-hot temperatures, harvesting the emitted light via thermophotovoltaic cells.
The company has demonstrated thermophotovoltaic cells with over 40% conversion efficiency, potentially outperforming lithium-ion batteries in cost and storage duration at grid scale. While claims are promising, this technology is in prototype and testing phases, cycling materials at extremely high operational temperatures to validate long-term performance and reliability.
Source & further reading
Turning extreme heat into large-scale energy storage ↗Source published 2026-03-18. This report was prepared with AI assistance from the linked primary-source material. Claims and limitations should be checked against the original announcement or research.