Spray-on battery

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 day be incorproated into industry.  Dr Pulickel Ajayan said: 'This means traditional packaging for batteries has given way to a much more flexible approach that allows all kinds of new design and integration possibilities for storage devices.

 'There has been a lot of interest in recent times in creating power sources with an improved form factor, and this is a big step forward in that direction.'  The team was led by graduate student Neelam Singh and it spend hours formulating and mixing paints to make up each of the five layered components - two current collectors, a cathode, an anode and a polymer separator in the middle.  In tests, nine bathroom tile-based batteries were connected in parallel. One was topped with a solar cell that converted power from a white laboratory light.  Once painted on the tiles were infused with electrolyte, heat sealed and charged.

 

 When fully charged by both the solar panel and house current, the batteries alone powered a set of light-emitting diodes that spelled out 'RICE' for six hours; the batteries provided a steady 2.4 volts.  The lithium-ion battery has been tested on bathroom panels, producing a steady 2.4 volts and being recharged by a solar cell  Ms Singh said: 'The hardest part was achieving mechanical stability, and the separator played a critical role.  'We found that the nanotube and the cathode layers were sticking very well, but if the separator was not mechanically stable, they would peel off the substrate.'  Scaling them up would increase power 'in leaps and bounds', she said, adding: 'Spray painting is already an industrial process, so it would be very easy to incorporate this into industry.'  The researchers have filed for a patent on the technique.  'We really do consider this a paradigm changer,' said Singh.