In this video, posted by the Florida Institute for Human & Machine Cognition, we hear about another 'battery' to store solar energy. The problem of course, is that you still need to buy all the solar equipment ($50,000/household).
Daniel G. Nocera and his researchers received media attention beginning in 2007 when he declared that a better understanding of the photosynthesis process could lead to economical storage of solar energy as chemical fuel. He later announced that his group had developed a highly efficient anode electrocatalyst (cobalt phosphate) for use in electrolysis of water employing inexpensive materials. His work on artificial photosynthesis centers around the basic mechanisms of energy conversion in biology and chemistry, particularly in the theory of proton coupled electron transfer. He is also the director of the Solar Revolution Project at MIT which seeks to create innovations in photocatalytic water splitting towards the use of solar energy in large scale, mainstream applications.