A yarn-like battery prototype that functions when submerged in seawater is described by researchers in ACS Applied Materials and Interfaces.
After soaking in salty water, these rechargeable strands lit up LEDs (top image) and powered a timer (bottom image). Image Credit: Adapted from ACS Applied Materials & Interfaces 2024, DOI: 10.1021/acsami.4c16439
Most batteries are stiff and incompatible with water. However, individuals who work and play in the oceans and estuaries could benefit from flexible and saltwater-safe power sources. They tied the rechargeable strands into a fishing net that illuminated LEDs and wove a fabric that powered a timer.
Flexible, yarn-like batteries can be weaved or knitted into various shapes. These stringy energy sources are lightweight and frequently engineered to be waterproof. Rather than completely avoiding battery exposure to water, scientists have advocated employing salty water as a key battery component: the electrolyte.
Yan Qiao, Zhisong Lu, and colleagues previously created a water-friendly battery using carbon fiber and cotton yarn. This previous research employed perspiration from the body as an electrolyte for workout monitors. Seawater, which includes salt, chloride, and sulfate ions, can be used as an electrolyte, similar to sweat. So Qiao, Lu, and a new team created a marine version of a rechargeable, yarn-like battery that could power lights on fishing nets, life jackets, and buoy mooring lines.
To make electrodes for seawater batteries, the researchers coated carbon fiber bundles with electrically conductive materials: nickel hexacyanoferrate for the positive electrode (cathode) and polyamide for the negative electrode (anode). Researchers then twisted two bundles together to create yarn-like cathode and anode strings.
To make a battery, the researchers wrapped the cathode string in fiberglass, put it along the anode, and covered both strands in a nonwoven, permeable material. The fabric shields the electrodes while yet enabling seawater to contact them. In saltwater testing, the battery maintained an electrical charge even after being bent 4000 times. Then, when tested in seawater, it preserved most of its initial charging efficiency and storage capacity after 200 charge and discharge cycles.
Finally, as a proof of concept, the crew strung battery strands together to form a fishing net and wove a rectangular piece of fabric. The net was then immersed in seawater to absorb the electrolyte and charged. The net battery illuminated a 10-LED panel. Similarly, the fabric soaked in a sodium sulfate solution ran a timer for almost an hour. The researchers believe their yarn-like battery has potential as an energy source in marine applications.
The authors acknowledge funding from the Chongqing Natural Science Foundation, the Sichuan Science and Technology Program, Southwest University's Innovation Research 2035 Pilot Plan, and the General Administration of Sport of China's Science and Technology Innovation Program.
The authors appreciate financing from the Chongqing Natural Science Foundation, the Sichuan Science and Technology Program, Southwest University's Innovation Research 2035 Pilot Plan, and China's General Administration of Sport's Science and Technology Innovation Program.
Journal Reference:
Jian, Y., et al. (2024) Constructing High-Performance Yarn-Shaped Electrodes via Twisting-after-Coating Technique for Weavable Seawater BatteryClick to copy article link. ACS Applied Materials & Interfaces. https://doi.org/10.1021/acsami.4c16439