Drying stresses in precursor gel: effect on pore connectivity in carbonized form, and resulting performance in a supercapacitor electrode

The presence of vapor-liquid interface, and more specifically the pressure gradient across such interface at the time of drying the precursor gel may significantly alter the pore structure in dry form, and in turn the pore hierarchy in the carbonized form. Here, the pore structure of carbon powder samples is analyzed, where the precursor gel prior to carbonization was subjected to vacuum-driven or atmospheric evaporation, and also lyophilization that avoids vapor-liquid interface altogether. The mesopores, originating from the void space that was left by the solvent in precursor gel contributed significantly in providing access of micropores to the electrolyte ions. Further, the role of pore activation by surface etching or through intercalation is discussed in this context. How the chemical and physical activation play out on carbon samples with different drying histories is analyzed. Mesoporosity enhancement through control of drying stress Micropore activation plays out differently to respective stress-affected pore structures. [GRAPHICS] HighlightsMesoporosity by control of drying stresses.Role of mesopores in transport of electrolyte ions during charge-discharge.Effectiveness of activation protocols depending on the mesopore size distribution.Role of activation on microporosity and quality of double layer.