US scientists build battery that stores energy as heat at 4,350°F in carbon blocks

Carbon blocks glowing white-hot at nearly half the temperature of the Sun's surface could revolutionize how we store clean energy. MIT spinout Fourth Power has developed thermal batteries that store electricity as heat at a scorching 4,350 degrees Fahrenheit, using molten tin to transfer that energy through massive graphite blocks.

When it's time to release power, the incandescent carbon emits intense light that gets converted back to electricity through specialized solar-like panels with over 40 percent efficiency.

The extreme temperatures are the key to success. "We realized if you push the temperature higher, you will transfer heat at a higher rate and shrink the system," explains Asegun Henry, the MIT heat transfer professor behind the technology.

Unlike metals that degrade in such heat, graphite thrives, allowing the system to cycle repeatedly while losing just one percent of stored energy daily. The modular design can provide 10 to 100 hours of power at costs far below lithium-ion batteries, positioning it as a game-changer for utilities struggling to store renewable energy for windless, cloudy days.