Solvent-tethered strategy enables the eutectogel integrated electrode with high conductivity and low-temperature resistance applying for supercapacitors

Abstract

As demand for wearable electronic devices grows, developing flexible supercapacitors with gel electrolytes has become imperative. To address the low conductivity and poor low-temperature resistance of conventional gel electrolytes, herein, a novel solvent-tethered strategy is proposed and the in-situ polymerization is employed to prepare the eutectogel integrated electrode with high conductivity and low-temperature resistance. Specifically, glycerol (GLy) is incorporated as a tether to bind with acrylic acid (AA, hydrogen bond donor), thus allowing it easier for the quaternary ammonium cations (Ch⁺) of the choline chloride (ChCl, hydrogen bond acceptor) to migrate, thereby improving the ionic conductivity. Theoretical validation via density functional theory confirms the feasibility of this strategy. The resulting eutectogel electrolyte (CAG-1.2) exhibits a high conductivity of 17.0 mS cm⁻¹ at room temperature and remains unfrozen at −90 °C. Moreover, the symmetrical electrode supercapacitor based on CAG-1.2 delivers a specific capacitance of 170 F g⁻¹ and demonstrates remarkable cycling stability over 40,000 cycles, operating effectively even in extreme environments. This strategy provides a new theoretical reference for designing high-performance flexible electronic devices.