Thanks to a molecule called fulvalene diruthenium, batteries may use the sun to provide energy, but not in the same way as solar power.
Here's how it works:
The molecule, fulvalene diruthenium, undergoes a structural change when it absorbs sunlight, putting it into a higher energy state where it can remain stable indefinitely. This state is analogous to that of a rubber band that's stretched and then put somewhere where it stays stretched out for any desired length of time.The technique would have a lot of the benefits of solar energy, but it'd store the heat as a fuel that could heat your house. Unfortunately, the molecule is prohibitively expensive, but scientists are hopeful that they can replicate the process with something cheaper.
In the case of fulvalene diruthenium, the molecule can snap back into its original shape triggered by a small addition of heat or a substance called a catalyst. In the process, it releases the heat that was originally absorbed.
Via World Science