Significantly enhanced rate capability in supercapacitors using carbide-derived carbons electrode with superior microstructure

Mesoporous carbide-derived carbons (CDC) with hierarchical pore structure were fabricated by chlorine etching of mesoporous titanium carbides. Their capacitive behaviors for electrochemical capacitor were investigated in comparison to those of purely microporous CDC. The as-prepared mesoporous CDC exhibited not only uniform micropores formed by leaching out titanium atoms but a 3-D mesoporous network inherited from their parent carbides. These mesoporous CDC could deliver a high specific capacitance of 120 F g⁻¹ in 1 M tetraethylammonium tetrafluoroborate dissolved in propylene carbonate. Moreover, they owned excellent frequency response and superior rate capability with capacitance retention ratio of 91% at current density of 10 A g⁻¹. A high energy density of 16.3 Wh kg⁻¹ was obtained even though power density was raised up to 4,300 W kg⁻¹. The distinctive capacitive performance of mesoporous CDC would be attributed to their superior microstructure, in which the uniform micropores contributed to high charge storage while the 3-D mesoporous network and nanometer-scaled dimension of particles facilitated ions transfer as well as shortened electrolyte diffusion distance.