Oxford team develops soft hydrogel lithium-ion battery

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Researchers have developed a soft hydrogel lithium-ion battery that could be used in several biomedical applications, including the defibrillation and pacing of heart tissues.

The development of tiny, soft and biocompatible batteries to power minimally invasive biomedical devices is of critical importance. Here the authors present a microscale soft rechargeable lithium-ion battery based on the surfactant-supported assembly of silk hydrogel droplets. Scale bar: 400μm
The development of tiny, soft and biocompatible batteries to power minimally invasive biomedical devices is of critical importance. Here the authors present a microscale soft rechargeable lithium-ion battery based on the surfactant-supported assembly of silk hydrogel droplets. Scale bar: 400μm - Image credit: Yujia Zhang

The work from Oxford University has been published in Nature Chemical Engineering.

The development of tiny smart devices sized smaller than a few cubic millimetres will require equally small power sources. For minimally invasive biomedical devices that interact with biological tissues, these power sources must be fabricated from soft materials and include features such as high capacity, biocompatibility and biodegradability, triggerable activation, and the ability to be controlled remotely. To date, there has been no battery that can fulfil these requirements simultaneously.

To address these requirements, researchers from the Oxford University’s Department of Chemistry and Department of Pharmacology have developed a miniature, soft lithium-ion battery constructed from biocompatible hydrogel droplets.

Surfactant-supported assembly is used to connect three microscale droplets of 10 nanolitres volume. Different lithium-ion particles contained in each of the two ends then generate the output energy.

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“Our droplet battery is light-activated, rechargeable, and biodegradable after use. To date, it is the smallest hydrogel lithium-ion battery and has a superior energy density’ lead researcher Dr Yujia Zhang from Oxford’s Department of Chemistry said in a statement. “We used the droplet battery to power the movement of charged molecules between synthetic cells and to control the beating and defibrillation of mouse hearts. By including magnetic particles to control movement, the battery can also function as a mobile energy carrier.’

Proof-of-concept heart treatments were carried out in the laboratory of Professor Ming Lei from Oxford’s Department of Pharmacology, a senior electrophysiologist in cardiac arrhythmias.

He said: “Cardiac arrhythmia is a leading cause of death worldwide. Our proof-of-concept application in animal models demonstrates an exciting new avenue of wireless and biodegradable devices for the management of arrhythmias.”

Professor Hagan Bayley from Oxford’s Department of Chemistry), the research group leader for the study, said: “The tiny soft lithium-ion battery is the most sophisticated in a series of microscale power packs developed by Dr Zhang and points to a fantastic future for biocompatible electronic devices that can operate under physiological conditions.”

The researchers have filed a patent application through Oxford University Innovation. They believe the battery, which they said is particularly relevant to small-scale robots for bioapplications, will open up new possibilities in various areas including clinical medicine.

soft hydrogel lithium-ion battery