Fluorine-free water-in-ionomer electrolytes for sustainable lithium-ion batteries.

ABSTRACT: The continuously increasing number and size of lithium-based batteries developed for large-scale applications raise serious environmental concerns. Herein, we address the issues related to electrolyte toxicity and safety by proposing a "water-in-ionomer" type of electrolyte which replaces organic solvents by water and expensive and toxic fluorinated lithium salts by a non-fluorinated, inexpensive and non-toxic superabsorbing ionomer, lithium polyacrylate. Interestingly, the electrochemical stability window of this electrolyte is extended greatly, even for high water contents. Particularly, the gel with 50?wt% ionomer exhibits an electrochemical stability window of 2.6?V vs. platinum and a conductivity of 6.5 mS cm-1 at 20?°C. Structural investigations suggest that the electrolytes locally self-organize and most likely switch local structures with the change of water content, leading to a 50% gel with good conductivity and elastic properties. A LiTi2(PO4)3/LiMn2O4 lithium-ion cell incorporating this electrolyte provided an average discharge voltage?>?1.5?V and a specific energy of 77?Wh?kg-1, while for an alternative cell chemistry, i.e., TiO2/LiMn2O4, a further enhanced average output voltage of 2.1?V and an initial specific energy of 124.2?Wh?kg-1 are achieved.

SUBMITTER: He X 

PROVIDER: S-EPMC6294254 | biostudies-other | 2018 Dec

REPOSITORIES: biostudies-other