2 research outputs found
Composite Manganese Oxide Percolating Networks As a Suspension Electrode for an Asymmetric Flow Capacitor
In this study, we examine the use
of a percolating network of metal oxide (MnO<sub>2</sub>) as the active
material in a suspension electrode as a way to increase the capacitance
and energy density of an electrochemical flow capacitor. Amorphous
manganese oxide was synthesized via a low-temperature hydrothermal
approach and combined with carbon black to form composite flowable
electrodes of different compositions. All suspension electrodes were
tested in static configurations and consisted of an active solid material
(MnO<sub>2</sub> or activated carbon) immersed in aqueous neutral
electrolyte (1 M Na<sub>2</sub>SO<sub>4</sub>). Increasing concentrations
of carbon black led to better rate performance but at the cost of
capacitance and viscosity. Furthermore, it was shown that an expanded
voltage window of 1.6 V could be achieved when combining a composite
MnO<sub>2</sub>-carbon black (cathode) and an activated carbon suspension
(anode) in a charge balanced asymmetric device. The expansion of the
voltage window led to a significant increase in the energy density
to ∼11 Wh kg<sup>–1</sup> at a power density of ∼50
W kg<sup>–1</sup>. These values are ∼3.5 times and ∼2
times better than a symmetric suspension electrode based on activated
carbon