Characterization and prediction of double-layer capacitance of nanoporous carbon materials using the Quantitative nano-Structure-Property Relationship approach based on experimentally determined porosity descriptors

Abstract

The development of nanoporous carbon-based energy storage is a fast-growing area. To assist these developments, it is necessary to establish simple criteria and relationships between electric double-layer (EDL) capacitance and the nature of porous carbon used as an electrode material. Under special attention is carbide-derived carbon (CDC) due to high content of micropores and well tunable pore size distribution. In the current study, experimentally determined structure descriptors were compiled for 110 CDC materials, and the Quantitative nano-Structure-Property Relationship (QnSPR) approach was used for the statistical analysis and modelling of the EDL capacitance. Experimentally determined structure descriptors – the variable numeric porosity characteristics of CDC materials, were determined from N2 and CO2 adsorption measurements. Electrochemical characterization of CDC based electrodes was performed in 3-electrode test-cells using carbon reference electrode and 1.5 M spiro-(1,1′)-bipyrrolidinium tetrafluoroborate (SBP–BF4) in acetonitrile as the electrolyte. It was shown that combining experimentally derived molecular descriptors of porosity, like specific surface area and volume-fractions of pore size distribution, calculated by density functional theory, allows accurate prediction of EDL capacitance. The QnSPR-s describing the gravimetric (R2 = 0.91) and the volumetric cathodic capacitances (R2 = 0.95) were developed for the nanoporous carbon in SBP–BF4 electrolyte.