ℵ₀ 🏳️‍⚧️🏴‍☠️Sep 29, 2023

https://www.nature.com/articles/s41563-023-01673-3

1/
#Polyethylene #terephthalate (PET) tape is widely used by well-known #lithium-ion #battery manufacturers to prevent electrode stacks from unwinding during assembly. PET tape is selected since it has suitable #mechanical and #electrical properties, but its #chemical stability has been largely overlooked.

Improving lithium-ion cells by replacing polyethylene terephthalate jellyroll tape - Nature Materials

Polyethylene terephthalate (PET) tape is widely used for lithium-ion batteries but its chemical stability has been largely overlooked. Reversible self-discharge is now shown to be virtually eliminated in LiFePO4–graphite cells by replacing PET with polypropylene jellyroll tape.

Nature
Show threadℵ₀ 🏳️‍⚧️🏴‍☠️
2/
In the absence of effective electrolyte additives, PET can #depolymerize into its monomer dimethyl terephthalate, which is an unwanted #redox shuttle that induces substantial self-discharge in a lithium-ion cell. This study presents a chemical screening experiment to probe the PET decomposition mechanism involving in situ generated methanol and lithium methoxide from dimethyl carbonate, one of the most common #electrolyte #solvents in lithium-ion cells.
Sep 29, 2023 at 6:39pmWeb
Show threadℵ₀ 🏳️‍⚧️🏴‍☠️Sep 29, 2023
3/
By screening other #polymers, it is found that #polypropylene and #polyimide (#Kapton) are stable in the #electrolyte. Finally, it is demonstrated that reversible self-discharge of LiFePO4–graphite cells can be virtually eliminated by replacing PET jellyroll tape with chemically stable #polypropylene tape.