A spray-on battery could revolutionise technology - allowing for slimmer gadgets, and household gizmos with built-in power supplies. The lithium-ion battery, which can be painted on to virtually every surface, works by 'spraying on' the chemical layers which form a battery. The new battery could make solar gadgets practical by building up their storage, without hefty long-life batteries building up their bulk. It has already been tested on bathroom panels, producing a steady 2.4 volts and being recharged by a solar cell, says Nature's Scientific Reports. Hailed as a 'paradigm changer' by creators at Rice University the technology could one...