Scientists at Nanyang Technological University in Singapore have created a paper-based battery that is fully biodegradable in soil after about a month. The battery could eventually be used in non-disposable, flexible electronic devices and smart fabrics.
One version of the battery is just 4 by 4 cm (1.6 in) and can power a small electric fan for 45 minutes, researchers report. Additionally, its power output isn’t interrupted if it’s bent or twisted, or even if pieces of it are cut off.
At the heart of the battery is a sheet of cellulose paper, which has been reinforced with a hydrogel to fill the gaps between the cellulose fibers. The paper serves as the separator between the anode and the cathode, which are screen-printed on opposite sides of the paper.
The conductive ink used to print the anode consists mainly of zinc and carbon black, while both manganese and nickel have separately been used for the cathode ink. After the electrode-printing process, the battery is immersed in an electrolyte solution, and then a thin layer of gold is applied to both electrodes to increase their conductivity.
“When decomposition happens, the electrode materials are released into the environment,” says Prof. Fan Hongjin, who is leading the study along with Asst. Prof. Lee Seok Woo. “The nickel or manganese used in the cathodes will remain in their oxide or hydroxide forms, which are close to the form of natural minerals. The zinc found in the anode will be naturally oxidized to form a non-toxic hydroxide. This points to the battery’s potential as a more sustainable alternative to current batteries.”
The research is described in a paper published in Advanced Science.
Source: Nanyang Technological University and www.newatlas.com.