1 research outputs found
Investigation into Pseudo-Capacitance Behavior of Glycoside-Containing Hydrogels
Electrochemical pseudocapacitors
are an attractive choice for energy
storage applications because they offer higher energy densities than
electrostatic or electric double layer capacitors. They also offer
higher power densities in shorter durations of time, as compared to
batteries. Recent efforts on pseudocapacitors include biocompatible
hydrogel electrolytes and transition metal electrodes for implantable
energy storage applications. Pseudocapacitive behavior in these devices
has been attributed to the redox reactions that occur within the electric
double layer, which is formed at the electrode–electrolyte
interface. In the present study, we describe a detailed investigation
on redox reactions responsible for pseudocapacitive behavior in glycoside-containing
hydrogel formulations. Pseudocapacitive behavior was compared among
various combinations of biocompatible hydrogel electrolytes, using
carbon tape electrodes and transition metal electrodes based on fluorine-doped
tin oxide. The hydrogels demonstrated a pseudocapacitive response
only in the presence of transition metal electrodes but not in the
presence of carbon electrodes. Hydrogels containing amine moieties
showed greater energy storage than gels based purely on hydroxyl functional
groups. Furthermore, energy storage increased with greater amine content
in these hydrogels. We claim that the redox reactions in hydrogels
are largely based on Lewis acid–base interactions, facilitated
by amine and hydroxyl side groups along the electrolyte chain backbones,
as well as hydroxylation of electrode surfaces. Water plays an important
role in these reactions, not only in terms of providing ionic radicals
but also in assisting ion transport. This understanding of redox reactions
will help determine the choice of transition metal electrodes, Lewis
acid–base pairs in electrolytes, and medium for ionic transport
in future biocompatible pseudocapacitors