Enhanced Power Performance of Highly Mesoporous Sol-Gel TiC Derived Carbons in Ionic Liquid and Non-Aqueous Electrolyte Based Capacitors

Abstract

The electrical double layer capacitors (EDLC) based on hierarchical micro-mesoporous sol-gel TiC derived carbon (SgTiC-CDC) electrodes and 1-ethyl-3-methylimidazolium tetrafluoroborate (EtMeImBF 4 ) and 1M Et 3 MeNBF 4 + acetonitrile (AN) as the electrolytes were tested to establish the electrochemical characteristics and region of ideal polarizability. The precursors for the micro-mesoporous carbon electrodes were synthesized via modified sol-gel synthesis process. Compared to traditional titanium carbide derived carbons, where precursor carbide is commercially available, the sol-gel TiC derived hierarchical carbon materials exhibit larger specific density functional theory (DFT) surface areas (up to 1700 m 2 g −1 ) and an unique pore size distribution with more mesopores between 2 and 10 nm. The electrochemical properties of the EDLCs were investigated using the cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic charge/discharge and constant power discharge methods. The EDLCs demonstrated nearly ideal capacitive behavior even at very high charging/discharging currents (10 A g −1 ) and cell potential scan rates (500 mV s −1 ). The EDLCs completed from SgTiC-CDC materials and EtMeImBF 4 and Et 3 MeNBF 4 + AN show good energy efficiencies (varying from 93% to 95% at current 1 A g −1 ) and coulombic efficiency values exceeded 99%. Thus, the EDLCs completed are very promising devices for extremely high power/energy density applications.

Non-Aqueous Zn-Ion Hybrid Supercapacitors: Acetonitrile vs Propylene Carbonate Based Electrolyte

“…4e, inset), and τ 2 very strongly depends on the cell potential applied as well as on the electrolyte composition under study. 44 For non-aqueous ZIHS cells, filled with different electrolytes, τ 2 value decreases in the order: Zn(OTf) 2 /AN > Zn(TFSI) 2 /PC > Zn(BF 4 ) 2 /PC > Zn(TFSI) 2 /AN > Zn(BF 4 ) 2 /AN, being the shortest for Zn(BF 4 ) 2 /AN solution containing cell (not shown for shortness).…”

“…where E out is energy released and E in is the energy accumulated during constant current charging cycle. 44,50 The stability of system under study has been tested using the long lasting constant current charge/discharge method at 2 A g −1 . Data in Fig.…”

Porous Carbons Activated by Different Methods as Positive Electrode Materials for Zn-Carbon Capacitors

“…Accordingly, the development of such materials is actively pursued. [8][9][10][11][12][13][14][15][16][17][18][19][20][21] Carbon materials are the most studied candidates and can offer excellent input/output densities. Systems with a carbon positive electrode depend on an electrical double layer for reversible ionic physisorption/desorption, and the capacity of the entire system is determined by the double layer capacitance and pseudocapacitance.…”