The main benefit compared to photovoltaic cells plus classic batteries appears to be the fact that one chemical, a liquid, does both the energy absorption from the sun and serves as the storage medium. And it's long term storage. Also easy to transport.
It works based on a specially designed molecule that changes shape when it comes into contact with sunlight, storing energy. And that energy is later released at any point in time as heat by running the chemical through a catalyst, and converted into electricity in a small chip-scale thing.
Obviously, this is still early research, long way until it's a freely available and economically viable technology. Still great tho, looks promising. I wonder how much energy it packs per kg or liter.
"Half" is stretching it. More like a slice: UK, Ireland, Iceland, Portugal, Spain and a slice of France.