Mechanically Stable UV‐Crosslinked Polyester‐Polycarbonate Solid Polymer Electrolyte for High‐Temperature Batteries

Abstract

Due to the mechanism with which solid polymer electrolytes use to conduct ions, these materials are generally more suitable for high‐temperature applications where the ionic conductivity is sufficient and where liquid electrolytes show insufficient stability. To enable high‐temperature cycling of polymer electrolytes, the mechanical stability has to be improved. Herein, we report successful long‐term cycling of a solid polyester‐polycarbonate – poly(ϵ‐caprolactone‐co‐trimethylene carbonate) (poly(CL‐co‐TMC)) – electrolyte cross‐linked through the addition of multifunctional acrylates and the use of UV‐irradiation, allowing stable cycling of cells for more than 100 cycles at 80 °C, with good rate capabilities (0.2 mA cm−2) and Coulombic efficiencies exceeding 99 %. Both the mechanical properties and the ionic conductivity of the mechanically stabilized poly(CL‐co‐TMC) were investigated and optimized to reduce the frequency dependence of the moduli while still achieving an acceptable ionic conductivity at elevated temperature. These results indicate that the poly(CL‐co‐TMC) system can straight‐forwardly be modified to allow for higher‐temperature applications.

Crosslinked xylose-based polyester as a bio-derived and degradable solid polymer electrolyte for Li+-ion conduction

“…65 Mindemark and co-workers also recently reported ionic conductivity on the order of 10 −5 S cm −1 at 60 °C for a crosslinked polyester-polycarbonate. 66 Amongst other polyesters, Zhang and co-workers, for example, reported the highest ionic conductivity (4 × 10 −3 S cm −1 at 85 °C) in 2017 with a polycaprolactone-based SPE. 67 However, in their case the material also employed a polyacrylonitrile skeleton framework and succinonitrile as a filler molecule to enhance the conductivity.…”

Polyester‐ZrO2 Nanocomposite Electrolytes with High Li Transference Numbers for Ambient Temperature All‐Solid‐State Lithium Batteries

“…Until recently, room‐temperature operational all‐solid‐state lithium polymer batteries have largely been considered difficult to achieve, and cells have typically been cycled at elevated temperatures (55–80 °C) [11,36,41–43] . In this context, we can show that this P(CL 80 TMC 20 )‐based nanocomposite polymer electrolyte holds potential to be employed as a true NCPE, which can be seen from the charge‐discharge profile of the lithium half‐cell assembled using of P(CL 80 TMC 20 )−LiTFSI 0.28 −ZrO 2 (4 wt.%) and cycled at or close to ambient temperatures (21–30 °C); see Figure 8.…”

Functional polymers for lithium metal batteries

“…However, these copolymers have poor structural integrity and can be prone to dendrite penetration in LMBs. Thus, crosslinked SPEs were prepared by UV curing of PCL-co -PTMC in the presence of di-and tri-acrylate crosslinkers and a photoinitiator [129] . Improved mechanical stability, with no substantial effect on conductivity and good cycling performance in Li/LFP cells were obtained.…”