Effect of redox active multivalent metal salts on micellization of amphiphilic block copolymer for energy storage devices via SANS, DLS and NMR

Abstract

Considerable attention is clutched by aqueous metal ion rechargeable batteries owing to their high energy density, low cost, nonflammability, and much environmental benignity with a safer alternative. However, effective manipulation in the electrolyte, such as the addition of polymers in an aqueous electrolyte system, is ongoing to suppress the leakage and water splitting behavior to expand its utility as improved energy storage devices. Here, the structural self-assembly of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO53-PPO34-PEO53, Mol. Wt. = 6600 gm mol−1) block copolymer, Pluronic® F77 in aqueous solutions were investigated, and the effect of ionic additives especially cation influence onto micellar size by small-angle neutron scattering (SANS), dynamic light scattering (DLS) and proton nuclear magnetic resonance (1H NMR) were systematically studied. The micellar structural parameters obtained from SANS data analysis with core–shell model noticed a decrease in core radius, aggregation number, and hard-sphere radius of micelles proved overall demicellization phenomena when salts were added. The results were supported by DLS study where a similar trend in radial decrement and NMR peak shifting supported the SANS results. Moreover, elementary electrochemical investigations such as ionic conductivity and transport number were also carried out for the applications into aqueous rechargeable batteries and supercapacitors.