• Flexible batteries are the focus of cutting-edge research combining expertise in electronics, chemistry and materials.
• The toxicity of lithium-ion technology is hampering the development of smart devices that fit close to the human body.
• The Augmented Vision project highlighted the potential of fuel cells constructed from biocompatible materials.
In June 2023, the World Economic Forum released the following report: Top 10 emerging technologies of 2023included well-discussed topics such as sustainable computing, the metaverse to treat mental health, and generative artificial intelligence. However, this report begins with an innovation that has not yet received widespread media attention: flexible batteries. Research in this area is particularly dynamic, fueled by the development of intelligent textiles, flexible screens, and connected watches and bracelets.
The main advantage of our batteries is the fact that they can be charged automatically without any external energy source.
combine several approaches
In 2019, multifunctional materials researchers at ETH Zurich Prototype thin film battery It can be bent, stretched, and even twisted without interrupting the current supply. In 2020, team from stanford announced a project for wearable RFID energy-powered stickers that track health information, and in 2021. University of British Columbia group announced the development of a battery that utilizes a chemical reaction that is flexible, waterproof, and, unlike lithium-ion battery technology, safe to wear directly on the skin.
Project reported in the March 2023 issue of the journal nano energy has gone further with innovations that combine some of the above approaches. The mini-battery, which has no electrodes or wires, is charged by immersing it in biofuel, is 0.5 millimeters thick, and is flexible enough to safely assume human form. organ. In this case, it was developed to enhance smart contact lenses. It could act as a transparent screen that allows the wearer to access augmented reality, or it could work to flag and treat illnesses in people with chronic health conditions such as diabetes or glaucoma. Masu.
Developed by researchers in electronics, chemistry and biotechnology at Nanyang Technological University in Singapore, the battery’s electrodes are made from microscopic porous paper used to clean lenses. Built into the edge of the lens, it does not obstruct the wearer’s vision.
Self-charging capacity
When charging is required, place the lens in a storage case containing a glucose-based solution. The cathode is coated with copper hexacyanoferrate (CuHCFe) and glucose oxidase. The anode is made of polypyrrole (PPy), a polymer that is both electrically conductive and biocompatible, making it ideal for medical applications. Dipping the anode and cathode into glucose causes a chemical reaction that charges the battery. “The main advantage of our batteries is that they can be recharged automatically, without the need for an external energy source.” Sok Woo Lee, an associate professor specializing in energy storage at Nanyang Technological University in Singapore, points out. “But it can also function and recharge like a traditional battery if needed.”
Testing showed that the device can send data to your smartphone for 12 hours. More importantly, this demonstration was performed using an artificial human eye immersed in a solution of simulated tear fluid. Through a chemical reaction with the battery, the tear fluid generates enough electrical current to power his smart contact lenses. Theoretically, one battery can undergo 200 complete charge/discharge cycles.
Other low power accessories
The Singapore team is not the first to conduct research in this area. “The main problem with biofuel cells is their low power density. ” Seok Woo Lee explains. “Unlike batteries that provide power by simply being immersed in body fluids, our battery combines a biofuel cell with a charging case filled with a highly concentrated solution, resulting in a higher power density.”
Although this project with an augmented reality intraocular display looks very futuristic, its battery principles could soon be applied to other low-power portables that utilize other biocompatible solutions such as retinal lactate. It could pave the way for accessories. The research team also mentions electronic skin patches and oral and dental sensors in the article.
