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Polystyrene-Based Single-Ion Conducting Polymer Electrolyte for Lithium Metal Batteries
Lithium metal batteries are one of the more promising replacements for lithium-ion batteries
owing to their ability to reach high energy densities. The main problem limiting their commercial
application is the formation of dendrites, which significantly reduces their durability and renders
the batteries unsafe. In the present work, we used a single-ion conducting gel polymer electrolyte
based on a poly(ethylene-ran-butylene)-block-polystyrene (SEBS) block copolymer, which was functionalized
with benzenesulfonylimide anions and plasticized by a mixture of ethylene carbonate
and dimethylacetamide (SSEBS-Ph-EC-DMA), with a solvent uptake of 160% (~12 solvent molecules
per one functional group of the membrane). The SSEBS-Ph-EC-DMA electrolyte exhibits an ionic
conductivity of 0.6 mSmcm1 at 25 C and appears to be a cationic conductor (TLi+ = 0.72). SSEBSPh-
EC-DMA is electrochemically stable up to 4.1 V. Symmetrical Li|Li cells; further, with regard to
SSEBS-Ph-EC-DMA membrane electrolytes, it showed a good performance (~0.10 V at first cycles
and <0.23 V after 700 h of cycling at 0.1 mAcm2 and 0.05 mAhcm2). The LiFePO4|SSEBSPh-
EC-DMA|Li battery showed discharge capacity values of 100 mAhg1 and a 100% Coulomb
efficiency, at a cycling rate of 0.1C.