It always happens... a device that was intended to be used was supposed to be fully charged, but its battery died over time. However, this may soon disappear if battery manufacturers start using different types of tape.
When assembling commercial lithium-ion batteries, polyethylene terephthalate (PET) tape is used to prevent the electrode stack from loosening. While the polymer's mechanical and electrical properties are excellent, scientists at Canada's Dalhousie University point out that its chemical stability has been largely overlooked.
In tests conducted by these researchers, they found that when PET comes into contact with dimethyl carbonate, one of the most common electrolyte solvents used in lithium-ion batteries, it depolymerizes into its monomer molecule, dimethyl terephthalate.
Dimethyl terephthalate is an "unwanted redox shuttle," which basically sucks electrons from lithium-ion batteries slowly and steadily. Therefore, the battery discharges itself even if the device it powers is left idle.
After experiments, the scientists found that, unlike PET, polypropylene remains stable in the presence of dimethyl carbonate. Subsequent tests showed that when commercially available polypropylene tape was used instead of PET in lithium-ion batteries, self-discharge was reduced by 70% and battery life was extended by 10%.
The researchers note that switching to polypropylene tape should be a simple and easy process for battery manufacturers.
A paper on the research, led by PhD student Anu Adamson and associate professor Michael Metzger, was recently published in the journal Nature Materials.