Preparation of Comb-Shaped Polyether with PDMS and PEG Side Chains and Its Application in Polymer Electrolytes

TL;DR

This paper describes a new comb-shaped polymer that improves battery performance by balancing ionic conductivity at different temperatures.

Contribution

The novel contribution is the synthesis of a comb-shaped polyether with PDMS and PEG side chains to enhance polymer electrolyte performance.

Findings

PDMS segments prevent low-temperature conductivity loss but reduce high-temperature conductivity.

mPEG segments improve high-temperature conductivity but lower low-temperature performance with longer chains.

Abstract

Polyethylene oxide (PEO) is the most well-studied polymer used in solid polymer electrolytes (SPEs) for lithium ion batteries (Li-ion batteries). However, ionic conductivity is greatly reduced in the low temperature range due to the crystallization of PEO. Therefore, methods to suppress the crystallization of PEO at room temperature by cross-linking or introducing a branched structure are currently being investigated. In this study, we synthesized new comb-type ion-conducting polyethers with two different side chains such as polydimethylsiloxane (PDMS) and polyethylene glycol monomethyl ether (mPEG) segments as flexible and ion-conducting segments, respectively. The introduction of the PDMS segment was found to prevent a decrease in ionic conductivity in the low-temperature region, but led to an ionic conductivity decrease in the high temperature region. On the other hand, the introduction of mPEG segments improved ionic conductivity in the high-temperature region. The introduction of mPEG segments with longer chains resulted in a significant decrease in ionic conductivity in the low-temperature region.

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