Scientists in Texas have demonstrated a way of 'painting' rechargeable lithium-ion batteries onto surfaces, greatly expanding the potential for future development of portable electronics. The team, from Rice University, has succeeded in painting batteries onto a range of different surfaces, including common household objects, with 'no surface conditioning'. The batteries are made up of five layers measuring just 0.5mm thick in total and, according to the scientists that developed the technology, can be fabricated using conventional spray-painting equipment and techniques.

This diagram shows a conventional lithium-ion battery on the left, and on the right, a multilayer 'paintable' battery fabricated by spraying the different layers directly onto a target surface. Anode and cathode layers are separated by a specially-developed polymer (image: creative commons via nature.com).

This development - batteries that can be sprayed onto any surface, to follow any contour - has obvious potential for the next generation of portable devices, including tablet computers, smartphones and cameras. The creators of the technology also envisage painted batteries being paired with solar cells, with the potential to create 'standalone energy capture-storage hybrid devices in different configurations'.

You can read more about this new technology at BBC online and you can see the original report at nature.com.

'Spray-on' batteries: our opinion

The movement away from fixed cylindrical or cuboid form-factors for rechargeable batteries makes sense for a number of reasons. Most importantly it gives designers more freedom when creating new electronic devices, by removing the need to 'design around' a large, plastic-encased battery. Instead, the battery can be shaped around - or indeed sprayed onto - the inside surface of the device that it will be powering. The downside, of course, is that at present, rechargeable batteries have a lifespan considerably shorter than the devices that they're designed to power. 

How much longer before a camera's battery and memory is built into the device itself? A 'paintable' battery could be sprayed inside a camera's casing, allowing for more efficient use of interior space, and potentially much more ergonomic designs. 

Already, tablet computers like Apple's iPad and some portable computers are shipping with non user-replaceable batteries glued into the inside of their cases (the iPad's battery accounts for almost a quarter of its total weight). This isn't just a cynical ploy by manufacturers to prevent you from replacing their battery with a cheap third-party alternative, or force you to upgrade to a new model once the battery dies. Non-replaceable batteries with a more flexible form-factor allow their host devices to be slimmer and structurally stronger, and the space inside them to be used more efficiently.

There will probably always be a demand for replaceable batteries in some types of camera, but we would be surprised if 'unibody' designs didn't become more common in photographic hardware, as well as smartphones and tablets, in the years to come.

What do you think? Is this a good thing? Let us know in the comments.