Storage is the hard part of renewable energy. In this article, the researches used a molecule that captures sunlight and locks it into a strained, high-energy shape. It can hold that energy for months to years and then release it as heat on demand. The release of that energy makes water boil in about one second. Energy density is 1.65 MJ/kg, beating lithium-ion (~0.9 MJ/kg).
The interesting background is the inspiration of the method by the shape-shift DNA undergoes when UV light damages it. It's the chemistry of sunburn.
> Energy density is 1.65 MJ/kg, beating lithium-ion (~0.9 MJ/kg)
Lithium-ion produce electricity, that can be used by a heat pump to get a greater than 100% efficiency measured in heat/electricity. Heat pumps have like 300% of efficiency, sometimes more, but let's assume only a 200%. In that cases
If you need to heat things, this seems to be the way to go. And heating accounts for nearly half of global energy demand and is still mostly fossil-fueled (paraphrasing). This means that this puts a big dent in the need for fossil fuel to generate energy. And all without depending on Chinese materials. Note that this is in the very early stages of development; In software development terms, this appears to be in the "alpha" stage.