18 research outputs found
3D-printed conductive static mixers enable all-vanadium redox flow battery using slurry electrodes
State-of-the-art all-vanadium redox flow batteries employ porous carbonaceous
materials as electrodes. The battery cells possess non-scalable fixed
electrodes inserted into a cell stack. In contrast, a conductive particle
network dispersed in the electrolyte, known as slurry electrode, may be
beneficial for a scalable redox flow battery. In this work, slurry electrodes
are successfully introduced to an all-vanadium redox flow battery. Activated
carbon and graphite powder particles are dispersed up to 20 wt% in the vanadium
electrolyte and charge-discharge behavior is inspected via polarization
studies. Graphite powder slurry is superior over activated carbon with a
polarization behavior closer to the standard graphite felt electrodes.
3D-printed conductive static mixers introduced to the slurry channel improve
the charge transfer via intensified slurry mixing and increased surface area.
Consequently, a significant increase in the coulombic efficiency up to 95% and
energy efficiency up to 65% is obtained. Our results show that slurry
electrodes supported by conductive static mixers can be competitive to
state-of-the-art electrodes yielding an additional degree of freedom in battery
design. Research into carbon properties (particle size, internal surface area,
pore size distribution) tailored to the electrolyte system and optimization of
the mixer geometry may yield even better battery properties
Single module flow-electrode capacitive deionization for continuous water desalination
The search for novel desalination technologies has recently led to the introduction of flow-electrodes to capacitive deionization (CDI) processes, named as flow-electrode capacitive deionization (FCDI). Unlike classical CDI, which is a discontinuous or semi-continuous process due to the need for regeneration of the electrodes within the same module, flow-electrodes offer new design opportunities which enable fully continuous desalination processes as well as easily scalable systems. Here, we describe a novel system for the continuous desalination of water based on FCDI using a single flow-electrode and a single module. The flow-electrode is based on activated carbon powder suspended in water. During continuous operation of the system, a desalination rate of a 1Â g/L NaCl solution of up to 70% is achieved at water recoveries of up to 80%. Additionally we report very good current efficiencies: in case of 80% water recovery, the current efficiency is 0.93. The single flow-electrode single module process might reduce energy and investment costs and lower the threshold to a large scale implementation. Keywords: Capacitive deionization, Water desalination, Flow electrodes, Electrosorption, Suspension electrode