3 results
Search Results
Now showing 1 - 3 of 3
- ItemBest practice for electrochemical water desalination data generation and analysis(Maryland Heights, MO : Cell Press, 2023) Torkamanzadeh, Mohammad; Kök, Cansu; Burger, Peter Rolf; Ren, Panyu; Zhang, Yuan; Lee, Juhan; Kim, Choonsoo; Presser, VolkerElectrochemical desalination shows promise for ion-selective, energy-efficient water desalination. This work reviews performance metrics commonly used for electrochemical desalination. We provide a step-by-step guide on acquiring, processing, and calculating raw desalination data, emphasizing informative and reliable figures of merit. A typical experiment uses calibrated conductivity probes to relate measured conductivity to concentration. Using a standard electrochemical desalination cell with activated carbon electrodes, we demonstrate the calculation of desalination capacity, charge efficiency, energy consumption, and ion selectivity metrics. We address potential pitfalls in performance metric calculations, including leakage current (charge) considerations and aging of conductivity probes, which can lead to inaccurate results. The relationships between pH, temperature, and conductivity are explored, highlighting their influence on final concentrations. Finally, we provide a checklist for calculating performance metrics and planning electrochemical desalination tests to ensure accuracy and reliability. Additionally, we offer simplified spreadsheet tools to aid data processing, system design, estimations, and upscaling.
- ItemTin/vanadium redox electrolyte for battery-like energy storage capacity combined with supercapacitor-like power handling(Cambridge : RSC Publ., 2016) Lee, Juhan; Krüner, Benjamin; Tolosa, Aura; Sathyamoorthi, Sethuraman; Kim, Daekyu; Choudhury, Soumyadip; Seo, Kum-Hee; Presser, VolkerWe introduce a high performance hybrid electrochemical energy storage system based on an aqueous electrolyte containing tin sulfate (SnSO4) and vanadyl sulfate (VOSO4) with nanoporous activated carbon. The energy storage mechanism of this system benefits from the unique synergy of concurrent electric double-layer formation, reversible tin redox reactions, and three-step redox reactions of vanadium. The hybrid system showed excellent electrochemical properties such as a promising energy capacity (ca. 75 W h kg−1, 30 W h L−1) and a maximum power of up to 1.5 kW kg−1 (600 W L−1, 250 W m−2), exhibiting capacitor-like galvanostatic cycling stability and a low level of self-discharging rate.
- ItemSub-micron novolac-derived carbon beads for high performance supercapacitors and redox electrolyte energy storage(Washington D.C. : American Chemical Society, 2016) Krüner, Benjamin; Lee, Juhan; Jäckel, Nicolas; Tolosa, Aura; Presser, VolkerCarbon beads with sub-micrometer diameter were produced with a self-emulsifying novolac–ethanol–water system. A physical activation with CO2 was carried out to create a high microporosity with a specific surface area varying from 771 (DFT) to 2237 m2/g (DFT) and a total pore volume from 0.28 to 1.71 cm3/g. The carbon particles conserve their spherical shape after the thermal treatments. The controllable porosity of the carbon spheres is attractive for the application in electrochemical double layer capacitors. The electrochemical characterization was carried out in aqueous 1 M Na2SO4 (127 F/g) and organic 1 M tetraethylammonium tetrafluoroborate in propylene carbonate (123 F/g). Furthermore, an aqueous redox electrolyte (6 M KI) was tested with the highly porous carbon and a specific energy of 33 W·h/kg (equivalent to 493 F/g) was obtained. In addition to a high specific capacitance, the carbon beads also provide an excellent rate performance at high current and potential in all tested electrolytes, which leads to a high specific power (>11 kW/kg) with an electrode thickness of ca. 200 μm.