The Influence of Succinyl Groups and Lithium Perchlorate on Chitosan Membranes as Electrolyte Polymers

Abstract

SummaryThe needs of secondary batteries are increasing every year. Secondary batteries using a liquid electrolyte have weaknesses, such as prone to leakage and difficulty in its packing. A solid polymer electrolyte is one solution to resolve this problem. This study was conducted to determine the effect of succinyl group and lithium perchlorate on chitosan membranes as the polymer electrolyte. The succinyl chitosan was obtained by reacting chitosan with succinic anhydride in various compositions. Polymer electrolyte membranes were derived from succinyl chitosan with different ratios of lithium perchlorate. The deacetylation degree of chitosan was determined by 1H‐NMR spectrum is 80.26%. Synthesis of succinyl chitosan has been successfully carried out, which is indicated by the characteristic peaks of 1H‐NMR spectrum at chemical shift value of 2.7 ppm – 2.9 that correspond to the signal proton from methilen of succinyl groups of the succinyl chitosan. The substitution degree of N‐succinyl chitosan that was determined by NMR (Nuclear Magnetic Resonance) was 13.75% for Chi‐SC 1:1 and 70.84% for Chi‐SC 1:3. The presence of succinyl groups on chitosan can increase ionic conductivity values of the membrane, but the tensile strength of membrane decreases. The N‐Succinyl chitosan membrane with degree substitution of 70.84% and lithium perchlorate ratio of 5% (w/w) showed the ionic conductivity of 8.04 × 10−2 S.cm−1. Therefore, the membrane of succinyl chitosan‐lithium with 5% (w/w) lithium perchlorate could be potentially used as a polymer electrolyte for lithium‐ion battery applications.