Activated carbon xerogels derived from phenolic oil: Basic catalysis synthesis and electrochemical performances

Abstract

The competitiveness of European coal tar distillation plants could be improved by the revaluation of coal-derived liquids and rejects such as phenolic oils, which currently lack high-end applications. In this study, carbon gels were successfully prepared for the first time from phenolic oil by base-catalysed sol-gel polymerisation, by taking advantage of all the major components of phenolic oil rather than the pure, single-component phenolic precursors that are normally used in sol-gel routes. To increase the feasibility of industrial applications, the organic gels were dried under subcritical conditions and the resultant xerogels were submitted to carbonisation and chemical activation in a one-step process, using different KOH to organic gel mass ratios. The resultant ACs were applied as supercapacitor electrodes and attained higher electrochemical performances than carbon gels previously obtained from classic precursors: high capacitance retention up to 74.9% at 12 A g−1, energy and power densities up to 7.37 W h kg−1 and 5.70 kW h kg−1, respectively, high cycling stabilities up to 94.8% after 10,000 charge-discharge cycles, high rate capability of 66% under 1 V s−1 scan rate, and fast frequency response of 0.45 s.