Abstract
Supercapacitors have received much attention as large-scale energy storage devices for high power density and ultralong cycling life. In this work, sodium vanadate Na
V
O
/poly(3,4-ethylenedioxythiophene) (PEDOT) nanocables with deficient bridge oxygen at the interface (denoted Vo
-PNVO) have been tailored for supercapacitors through the
polymerization of 3,4-ethylenedioxythiophene and studied using three different electrolytes. Experiments and theoretical calculations reveal that all Na
, Zn
, and Al
ions appear as hydrates in aqueous solutions but insert into the crystal structure as Na
ions and Zn
-H
O and Al
-H
O hydrates, respectively. In comparison with the Zn
-H
O and Al
-H
O hydrates, Na
ions with a smaller radius diffuse more quickly in Vo
-PNVO. Thus, Vo
-PNVO delivers better charge storage capability and stability when an electrolyte with Na
ions is used. The results strongly suggest that an electrostatic interaction is significant in determining transport properties and storage capacities, rather than hydrate radii or valence states.