Influence of polyethylene glycol on pore structure and electric double-layer capacitance of carbon xerogel

Abstract

Mesoporous polyethylene glycol-resorcinol and formaldhyde (PEG-RF) carbon xerogels were prepared by a new polymer blend method in which PEG-RF mixed organic xerogels were synthesized by blending thermally unstable polyethylene glycol with organic monomers, resorcinol and formaldhyde and then subjected to pyrolization at 1 000 °C. The influences of mass ratio PEG to the theoretical yield of RF xerogel, m(PEG)/m(RF) and the relative molecular mass of PEG on the pore structure and electric double layer capacitance (EDLC) performance of PEG-RF carbon xerogels were investigated. The results show that PEG under different conditions leads to the difference of phase separation structure of the polymer blend and thus the change of pore structure of PEG-RF carbon xerogels. Specific surface area and capacity of PEG-RF carbon xerogels in 30% H₂SO₄ solution can reach 755 m²/g and 150 F/g, respectively. Their surface can be fully utilized to form electric double layer. However, the pore structure differences of PEG-RF carbon xerogels result in their different EDLC performances. The distributed capacitance effect increases with decreasing the pore size of PEG-RF carbon xerogels.

Keywords

polymer blend method / polyethylene glycol / carbon xerogel / electric double-layer capacitance

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