Specific Electrolyte for Supercapacitor {2.7 V, -40℃~70℃}, 200 g/bottle, CSCSEDL3611

Designing an electric double-layer capacitor (EDLC) or supercapacitor operating at a standard 2.7 V window across an extended temperature range of -40 ℃ to +70 ℃ requires balancing sub-zero ionic conductivity with high-temperature thermal stability and vapor-pressure suppression. While 2.7 V is less demanding on oxidative stability than 3.0 V systems, reaching +70 ℃ means pure low-boiling solvents (like neat acetonitrile) can generate excessive internal vapor pressure and risk cell bulging. Conversely, pure high-boiling solvents (like propylene carbonate) freeze or become too viscous at -40 ℃. A balanced binary co-solvent approach resolves this trade-off.

The recommended electrolyte recipe are shown below: (1) Salt Framework: 1.2 M Tetraethylammonium tetrafluoroborate (TEABF4). The TEABF4 is the industry standard for carbon-based EDLCs. It offers excellent dissociation, high ionic conductivity, and exceptional electrochemical stability up to and beyond 2.7 V without undergoing reductive or oxidative breakdown on high-surface-area activated carbon electrodes. (2) Solvent Architecture: (i) Core Solvents: Propylene Carbonate (PC) + Acetonitrile (AN) mixed at a volumetric ratio of PC : AN = 1 : 1 to 2 : 3 by volume. Acetonitrile (AN) provides the low viscosity and low freezing point necessary to maintain high ionic conductivity and low Equivalent Series Resistance (ESR) down to -40 ℃. Propylene Carbonate (PC) features a high boiling point (~242 °C) and suppresses the high-temperature vapor pressure of AN, ensuring structural safety and preventing dry-up or gas generation during continuous operation at +70 ℃.

Notes: Please store the specific supercapacitor electrolyte in the glovebox due to its sensitivity to humidity.

References: 

1. F. R. Hughson, et al. A 2.7 V Aqueous Supercapacitor Using a Microemulsion Electrolyte, Batteries & Supercaps, 2021, 4, 1122-1125.
2. L. Su, et al. Achieving a 2.7 V aqueous hybrid supercapacitor by the pH-regulation of electrolyte, J. Mater. Chem. A (2020) 8 (17): 8648–8660.