Researchers announced the development of a new lithium ion battery, stretchable up to 300% of the original size. The device can also be recharged wirelessly, making it suitable for biomedical applications, in the skin or biological tissues.
Lithium Ion Batteries
Lithium ion (Li+) batteries are a type of rechargeable battery in which the battery generates electrical energy by the movement of Li+ within the battery itself. Lithium is present in the form of a lithium salt, such as lithium cobalt oxide LiCoO2. The ions migrate from the negative electrode to the positive electrode, generating an electric current. If all ions migrate to the positive electrode, the battery has no charge left. However, it is possible to reverse this migration by inducing a movement of the ions in the opposite direction, from the positive electrode to the negative electrode, thereby recharging the battery.
Very Common Batteries
Li+ batteries are commonly used in electronic devices because they are lighter than other rechargeable batteries and may have higher charge density. They also lose their charge very slowly – less than 10% of the charge is lost in a month, approximately one-third less than the charge lost with other batteries, including nickel hydride. Lithium ion batteries are also rechargeable – for several cycles.
The main disadvantages of these batteries are their fragility and temperature sensitivity, so you should store them in safe and air-conditioned locations. There are also some safety issues associated with Li+ batteries due to the high reactivity of the lithium ion, so some restrictions may apply if you’re trying to transport large quantities of these batteries.
Flexible and Stretchable Batteries
In recent years, researchers have investigated the development of batteries and other optoelectronic devices on flexible and stretchable substrates. Possible flexible substrates are metal foils, paper sheets or polymer films. Rubber is also elastic and stretchable. We could use batteries with these mechanical properties in many different applications, including medical imaging, health monitoring and energy generation. Though researchers developed flexible devices successfully, there are more difficulties with the use of stretchable substrates. Stretchable devices tend to not be easily rechargeable and do not have good mechanical properties.
Researchers published an interesting and promising study on this type of material on February 26, 2013 in Nature Communications. The Department of Materials Science and Engineering of University of Illinois (US) performed the research, with other partners in the work: Tsinghua University (China), Northwestern University (US) and Hanyang University (South Korea).
In the resent study, the authors developed a Li ion battery on an elastic silicone substrate.
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