Low Temperature Performance of Electrochemical Double-Layer Capacitor based on Electrospun Half-Cells

Abstract

Electrochemical characteristics of the two identical electrospun microporous-mesoporous carbon electrodes deposited onto the electrospun nanofibrous polymer membrane layer have been studied in 1 M triethylmethylammonium tetrafluoroborate solution in acetonitrile at room and low temperature, 24°C and −30°C, respectively, by using cyclic voltammetry, constant current charge/discharge, electrochemical impedance spectroscopy and constant power discharge methods. The electrochemical double-layer capacitor (EDLC) half-cells have been prepared using a two step process: at first the nanowire polymer separator layer has been created by the electrospinning method, and thereafter the electrode material layer (microporous-mesoporous carbon powder with binder) has been directly electrospun onto the separator layer. Applying the electrospun half-cell preparation method we are able to prepare composite electrodes for EDLC with lower density and thickness of electrode pack than using the widely used traditional roll-pressing method. The wide region of ideal polarizability, high specific capacitance, low equivalent series resistance, short characteristic time constant and high specific energy and specific power values have been obtained and discussed for the completed EDLC working at 24°C and −30°C. The electrochemical characteristics of EDLC based on electrospun half-cells have been compared with those for EDLC completed using the roll-pressed thin (∼80 μm) electrodes.