Solid polymer electrolytes prepared from poly(methacrylamide) derivative having tris(cyanoethoxymethyl) group as its side chain

• Polymethacrylamide with tris(cyanoethoxy) group (PMCA) was used as SPEs' matrix.
• Highest conductivity of the PMCA-based electrolyte film was 0.12 mS cm− 1 at 343 K.
• Plating and stripping of Li in the PMCA-based electrolyte were observed.

A new methacrylamide monomer (MCA) was synthesized by coupling reaction between methacrylic acid and branched amine having tri(cyanoethoxymethyl) groups. PMCA was prepared by radical polymerization of MCA using AIBN as a radical initiator. The solid polymer electrolyte films were prepared from PMCA and lithium bis(trifluoromethanesulfonyl)amide, LiTFSA. The highest ionic conductivity for PMCA-based electrolyte films was 1.06 μS cm− 1 at 293 K and 0.12 mS cm− 1 at 343 K. Lithium salt (LiTFSA) dissolution in the PMCA-based electrolyte films was enhanced by the coordination of the lithium ions with the nitrile groups in the PMCA side chains. Ion conduction in the PMCA matrix was also affected by the motion of the tris(cyanoethoxymethyl) side chains in the PMCA matrix. The PMCA-based electrolyte film showed oxidation stability up to ca. 3.1 V against a lithium electrode. Reversible electrochemical plating and stripping processes of lithium was observed on a nickel plate in the PMCA-based electrolyte.