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<\/div>A tiny soft lithium-ion battery made from droplets<\/p>\n
University of Oxford<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
The smallest soft lithium-ion battery ever made consists of just three tiny droplets formed from a silk-based hydrogel. The droplet battery can deliver defibrillator electric shocks to beating mouse hearts, along with providing pacemaker-style control \u2013 but it may eventually power biomedical implants and wearable electronics for humans.<\/p>\n
\u201cPotentially, our tiny battery could be used as an implantable microrobotic battery, which can be moved to target locations by a magnetic field and then release its energy for medical treatments,\u201d says Yujia Zhang<\/a> at the University of Oxford.<\/p>\n Zhang and his colleagues designed the tiny batteries as three connected droplets that can self-assemble in a liquid solution, after the various ingredients are injected into the liquid by micro-syringe. One droplet contains lithium manganese oxide particles and acts as the battery\u2019s negative electrode, while a second droplet contains lithium titanate particles and represents the positive electrode. A central droplet filled with lithium chloride separates these electrodes. UV light activates the battery by rupturing the layers separating each droplet and allowing lithium ions to flow freely between them.<\/p>\n <\/p>\n The droplet batteries are 10 times smaller in length than previous soft lithium-ion batteries. At just 600 micrometres, it is about six times the width of a human hair. The batteries are also 1000 times smaller in volume than similar flexible lithium-ion batteries. And because the central droplet can incorporate magnetic nickel particles, the batteries can be controlled remotely via an external magnetic field.<\/p>\n Such miniature batteries also deliver an unprecedented amount of energy given their tiny size, says Wei Gao<\/a> at the California Institute of Technology. \u201cThis energy density is notably higher than what has been achieved in other similar-sized batteries,\u201d he says.<\/p>\n The droplet batteries were tested in mouse hearts that were removed from the animals\u2019 bodies. They successfully acted as defibrillators to restore a normal heartbeat and pacemakers to regulate heartbeats. Additional testing showed that the batteries retain 77 per cent of their original capacity after 10 charge and discharge cycles.<\/p>\n The simplicity and scalability of such droplet batteries<\/a> could represent a potential advantage over traditional battery manufacturing<\/a> in the future, says Gao. He suggested that such batteries can power minimally invasive biomedical implants and biodegradable medical devices.<\/p>\n \u201cWhat impressed me most was how this soft battery mirrors the aqueous environment of human tissue by being hydrogel-based,\u201d says Gao. \u201cHowever, we still need to consider the safety and biocompatibility of the materials used in this battery, especially as we move toward commercialisation or further research applications.\u201d<\/p>\n Topics:<\/p>\n<\/section><\/div>\n