Specific Electrolyte for Supercapacitor {2.85-3.0 V, -40℃~80℃}, 200 g/bottle, CSCSEDL3413

Designing a supercapacitor (Electric Double-Layer Capacitor, EDLC) operating at an aggressive voltage window of 2.85 V to 3.0 V across a wide thermal range of -40 ℃ to +80℃ pushes traditional organic electrolyte formulations to their absolute limits. At +80 ℃ combined with 3.0 V, standard acetonitrile-based electrolytes suffer from extreme vapor pressure and accelerated electrolyte oxidation, while pure high-boiling solvents freeze or cause sharp internal resistance (ESR) spikes at -40 ℃. To survive this environment, the formulation must employ an advanced salt and a high-boiling binary co-solvent system engineered to suppress both low-temperature viscosity barriers and high-temperature gas generation.

The recommended electrolyte recipe are shown below: (1) Salt Framework: 1.0 M Triethylmethylammonium spiro-bis(pyrrolidinium) tetrafluoroborate (TEMABF4) or 1.0 M Spiro-(1,1'-bipyrrolidine) tetrafluoroborate (SBPBF4). While standard TEABF4 can begin to show oxidative degradation or Hofmann-type elimination side-reactions at 3.0 V and +80 ℃, quaternary spirocyclic ammonium salts like SBPBF4 or TEMABF4 possess superior anodic stability windows (stable past 3.2 V vs. carbon) and higher thermal decomposition thresholds, preventing calendar-life fade at +80 ℃. (2) Solvent Architecture: (i) Core Solvents: Propylene Carbonate (PC) + y-Butyrolactone (GBL) mixed at a volumetric ratio of PC : GBL = 3 : 7 to 4 : 6 by volume. y-Butyrolactone (GBL) has a low melting point and low viscosity, ensuring that ion transport remains active and Equivalent Series Resistance (ESR) is kept within bounds down to -40 ℃. Propylene Carbonate (PC) provides a high boiling point (~242 °C) and excellent anodic stability. Together, this non-acetonitrile blend eliminates the dangerous vapor pressure build-up that pure low-boiling nitriles would experience at +80 ℃.

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

References: 

1. W. Y. Tsai, et al. Outstanding performance of activated graphene based supercapacitors in ionic liquid electrolyte from −50 to 80 °C, Nano Energy, 2013, 2, 403-411
2. S. W. Xu, et al. Temperature-dependent performance of carbon-based supercapacitors with water-in-salt electrolyte, Journal of Power Sources, 2019, 441, 227220.