Direct measurement of electrical conductivity of porous biochar monolith for supercapacitors

Abstract

Electrical conductivity of electrode plays a vital role in governing the performance of supercapacitor. However, the measurement of conductivity is difficult due to the complex pore structure and binder content in supercapacitor electrode. Characterization of the intrinsic conductivity of carbon network is significant for further understanding its supercapacitive behavior. In this paper, a direct conductivity measurement is adopted to investigate electron transport in biochar produced under different pyrolysis temperatures. Four-point probe technique is used to measure the apparent conductivity of porous biochar monolith. To eliminate the structure effect on conductivity, calculation based on Reynolds and Hough rule is provided to obtain the intrinsic conductivity of carbon network. The significance of electrical conductivity on the supercapacitive behavior is discussed.