Though only in their experimental, early stages, flexible electronics are starting to show some real promise for things like LED-laden clothes, medical sensors and fitness trackers. But powering these things is a huge challenge in itself, with rigid lithium-ion batteries unable to bend in-tune with devices without breaking, failing and possibly leaking out toxic and flammable materials. Researchers have developed a battery claimed to mitigate these risks, with the ability to "self-heal" in the event of a rupture.
Electrically conductive materials that can be bent and twisted are the backbone of the emerging field of advanced wearables, but providing them with a power source isn't so straightforward. We are starting to see researchers focus on flexible batteries that can withstand these forces, like those recently unveiled by Panasonic, Rice University researchers and scientists at the University of Illinois, for example.
But for a team of scientists from China's Fudan University, the Samsung Advanced Institute of Technology and the Samsung R&D Institute, part of the solution may lie elsewhere. Over the last few years, we have seen a line of self-healing polymers developed that might be put to use in self-mending bioplastics, airplane materials and scratch-resistant paints, and now the team is tuning the tech to more durable lithium-ion batteries.
Its battery design has layers of self-healing polymer that serve as substrates for layers of parallel carbon nanotubes, which act as the battery's electrodes. Lithium compounds are embedded in nanoparticle form in between these layers, as is a novel, solvent-free electrolyte made from a cellulose-based gel and an aqueous lithium sulfate solution.
The researchers say that when their battery is broken, it can be repaired simply by pressing each of the broken ends together. This causes the self-healing polymer and the carbon nanotubes to bind together in only a few seconds and apparently, return to full functionality even after the process is repeated multiple times.
Other advantages the new device is claimed to have over traditional lithium-ion batteries is that the lithium compounds are sealed inside and unable to leak out, and that unlike typically used electrolytes that decompose when exposed to air, their cellulose-based gel solution is stable and is not flammable or toxic.
The team's research was published in the journal Angewandte Chemie International Edition.