An ordered mesoporous carbon with short pore length and its electrochemical performances in supercapacitor applications

The pores of conventional ordered mesoporous carbons (OMCs) are usually over several micrometers in length, making it difficult for electrolyte access and ion diffusion to the deep pores of the carbon grains when they are used as the electrode of electrochemical double layer capacitors (EDLCs). We have synthesized an ordered mesoporous carbon with a much shorter pore length of 200-300 nm through a hard-template method. The electrochemical properties as an electrode material for EDLC were investigated in an alkaline solution in comparison with the conventional OMC. A maximum capacitance of 14 μF cm2 was obtained for this short pore length OMC (SOMC) in 6 M KOH solution compared with 10 μF cm2 of the conventional OMC. SOMC delivered much better capacity retention than the conventional OMC in lower concentration electrolyte solution. The superior performance of SOMCs was attributed to its having more entrances for electrolyte accessibility and a short pathway for rapid ion diffusion.