A team made up of researchers from the University of California San Diego and California-based company ZPower recently developed a flexible, rechargeable silver oxide-zinc battery with a five to 10 times greater areal energy density than standard batteries. Not only does it perform better than most commercial flexible batteries, but it's also easy to manufacture. Most flexible batteries require sterile conditions, under vacuum for manufacturing. This new battery can be printed in normal lab conditions, making it ideal for use in electronic wearables and soft robotics.
This battery's areal capacity is 50 milliamps per square centimeter at room temperature, which is 10 to 20 times greater than the areal capacity of your standard Lithium-ion battery. Due to its lower impedance or the resistance of an electric circuit or device to alternative current, the battery has a higher capacity than current flexible batteries.
The battery is made up of silver oxide-zinc chemistry, which helps increase its energy density. Most flexible batteries use an Ag2O-Zn chemistry, which gives them a limited life cycle and lower capacity. ZPower's AgO cathode material uses a lead oxide coating to improve its electrochemical stability and conductivity.
For manufacturing, the battery can be screen printed in just a few seconds. Once it's dry, it's ready to use. The batteries are printed onto a polymer film that is chemically stable, elastic and has a high melting point (about 200 degrees C or 400 degrees Fahrenheit) that can be heat sealed.
The team found the batteries could power a flexible display system equipped with a microcontroller and Bluetooth modules. It actually performed better than commercially available Li coin cells. And after being recharged for more than 80 cycles, the battery showed no signs of capacity loss. The team is currently working on the next version of the battery aiming for an even lower impedance and cheaper charging devices.