Flame-Retardant, Highly Conductive, and Low-Temperature-Resistant Organic Gel Electrolyte for High-Performance All-Solid Supercapacitors

Traditional liquid electrolytes are volatile, flammable, and easy to leak, which makes the energy storage device easy to burn and explode in the case of overcharge and short circuit. Here, by utilizing the active P-H bond of a flame retardant (DOPO) to graft onto the polymer chain, flame-retardant organic gel electrolytes were fabricated to address these issues. The gel electrolyte had good ionic conductivity of 4 mS cm(-1) at 20 degrees C and good flame retardant ability. By changing the molar ratio of the monomers and the salt concentrations, the mechanical strength of the gel electrolyte could be adjusted (maximum stress approximate to 28 KPa, maximum strain approximate to 305 %). The transport mechanism of lithium ions in the gel polymer electrolyte was proposed. The gel electrolyte-assembled supercapacitor (SC) possessed better electrochemical properties than that of SC assembled by liquid electrolyte. Importantly, the gel-based SC remained basically unchanged under multiple bending cycles. Additionally, the gel electrolyte had good low-temperature tolerance (0.1 mS cm(-1) at -40 degrees C). The gel electrolyte-assembled SC could work normally in the temperature range of -20 to 60 degrees C. The multiple advantages of gel electrolyte expand the applications in ionic conductor and energy storage devices.

Automated summary

By grafting a flame retardant onto the polymer chain, flame-retardant organic gel electrolytes were fabricated with good ionic conductivity, flame retardant ability, and adjustable mechanical strength. Compared to traditional liquid electrolytes, gel electrolytes show better electrochemical properties and can work normally in a wider temperature range. The multiple advantages of gel electrolytes expand the applications in ionic conductor and energy storage devices.