A team of mechanical engineers has published a paper demonstrating its latest invention — spray-on rechargeable batteries that could be combined with solar cells to create self-sufficient, energy conversion-storage devices.
By breaking down the different components of a battery - the electrodes, separator, electrolyte and current collectors - and rendering them into liquid form, we could revolutionize the way we power our devices.
Lithium-ion batteries are made by tightly rolling up the various battery components in layers before encasing them in rectangular or cylindrical packaging. The engineers, from Rice University in Texas, devised their own unique version of a multilayer battery by painting these individual battery components (two current collectors, a cathode, an anode and a polymer separator) on to select surfaces in layers. These layers included paints made from lithium cobalt oxide (a positive electrode), lithium titanium oxide (a negative electrode) and conductive single-walled nanotubes (a current collector). The special polymer paint blend helped achieve superior conductivity by forming the micro-porous layer required in a lithium battery.
The final paints were layered on to glass, stainless steel, glazed ceramic tiles and flexible polymer sheets — the resulting “batteries” worked just as well as the regular version. The team even picked out a choice ceramic mug, spray-painted the word “rice” in capital letters using a stencil, and demonstrated its efficiency as a battery.
Even more complex battery structures could be created, the paper added, using different nozzle fixtures on the spray cans.
The main drawback of the ingenious system is that lithium-ion batteries need oxygen-free, dry conditions to be created since they are made using toxic, flammable and corrosive materials.