Abstract
The use of pyrrolidinium‐based ionic liquids (ILs) in asymmetric electric double‐layer capacitors (AEDLC) with positive and negative carbon electrodes of different weight is a powerful strategy for developing safe, high specific‐energy supercapacitors operating at >3.5 V. The preparation and characterisation of ordered (OTC) and disordered (DTC) template carbons, the latter obtained by a fast and low‐cost method, are reported. The porosity and capacitance features of the template carbons are discussed in view of their application in IL‐based AEDLCs and compared with the properties of aero/cryo/xerogel carbons and a commercial activated carbon. The performance of an N‐butyl‐N‐methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide‐based AEDLC assembled with DTC carbon electrodes operating at 3.9 V featuring high specific energy of 47 Wh kg^–1^ is then reported. The impact of porosity and surface chemistry of carbons on the electrode capacitive response in IL and on the performance of the IL‐based AEDLC in terms of energy, power and weight distribution of module components is discussed. The effect of IL nature and carbon porosity on the time constant of the double‐layer charging process was also investigated by voltammetric and impedance studies.