The development of wearable and implantable electrical devices has been in great demand recently. However, most existing energy storage systems are based on strong corrosive or toxic electrolytes, posing a huge safety hazard as a result of solution leakage.
Here, we have developed a family of safe and flexible belt- and fiber-shaped aqueous sodium-ion batteries (SIBs) by using various Na+-containing aqueous electrolytes, including Na2SO4 solution, normal saline, and cell-culture medium. The resulting SIBs exhibit high flexibility and excellent electrochemical performance and can be safely applied in wearable electronics. Flexible SIBs with normal saline or cell-culture medium as the electrolyte showed excellent performance, indicating potential application in implantable electronic devices.
In addition, the fiber-shaped electrode in normal saline or cell-culture medium electrolyte can consume O2 and change the pH, implying promising application in biological and medical investigations.
In a lot of the flexible batteries out there, these electrolyte solutions are made out of strong acids or toxic chemicals, the study says. That stuff is corrosive, flammable, or toxic, and you definitely don’t want it dribbling onto or into your body. That’s why scientists at Fudan University in China came up with a way to replace these toxic electrolyte solutions with something much less harmful.
The researchers experimented with a few different types of electrolyte solutions. The one that worked best was sodium sulfate, which is sometimes used as a laxative. But saline solutions, which are literally diluted salt water, also worked well. Eventually, bodily fluids like blood, sweat, or tears might take over the roll of the electrolyte solution to power medical implants, the study says.