Effect of Mesopore Ordering in Otherwise Similar Micro/Mesoporous Carbons on the High-Rate Performance of Electric Double-Layer Capacitors

We probed the effect of structural mesopore ordering on the rate performance of supercapacitors using two carbon materials differing mainly in the ordering of mesopores, but displaying the same micropore size distributions, similar mesopore size distributions, and similar electrical conductivity. The material with ordered mesopores shows an excellent rate capability of ∼80% capacitance retention at a very high current density of 50 A g–1, whereas its disordered counterpart exhibits a capacitance retention of ∼60% at the same current density. On account of the similarities between the two carbons, the enhanced rate capability of highly ordered mesoporous carbon can be attributed to the straight channels of long-range highly ordered 2D hexagonal mesopores. This provides favorable conditions for ultrafast ion transport, suggesting the role of mesopores in high-rate operation to be more important than being an electrolyte reservoir only.