A marriage made in sunlight: Invention merges solar with liquid battery

As solar cells produce a greater proportion of total electric power, a fundamental limitation remains: the dark of night when solar cells go to sleep. Lithium-ion batteries, the commonplace batteries used in everything from hybrid vehicles to laptop computers, are too expensive a solution to use on something as massive as the electric grid.

Song Jin, a professor of chemistry at the University of Wisconsin–Madison, has a better idea: integrating the solar cell with a large-capacity battery. He and his colleagues have made a single device that eliminates the usual intermediate step of making electricity and, instead, transfers the energy directly to the battery’s electrolyte.