Using electrical conductivity to determine particle sedimentation status of carbon-based slurry electrodes in electrochemical energy storage systems

Impact of Current Collectors with Different Electrocatalytic Activities on Hydrogen Production in Microbial Electrolysis Cells with Flowable Cathodes

“…The most positive HER potentials with NF-Ni/AC compared to SS-Ni/AC and Ti-Ni/AC were likely attributed to the large active surface area of NF and its excellent electroactivity toward HER. The specific surface area reported for NF (∼128 m 2 /m 2 ) is 2 orders of magnitude larger than the one reported for pristine Ti plate (∼1.75 m 2 /m 2 projected area) and SS mesh (∼1.2 m 2 /m 2 projected area). ,, The previous studies reported higher conductivities as well as enhanced electrochemical activities of flow electrodes with a higher surface area of the current collector as the result of the enhanced frequency of random particle collisions and particle contact time with the current collectors. , Thus, both higher electroactivity toward HER and high surface area of NF likely promoted electrocatalytic activities of the Ni/AC flow cathodes. More positive HER potentials with higher Ni/AC loadings (for NF-Ni/AC and SS-Ni/AC) are likely due to the improved onset potentials for HER since those NF and SS mesh are HER-active current collectors (Figure ).…”

“…16,17,19 The previous studies reported higher conductivities as well as enhanced electrochemical activities of flow electrodes with a higher surface area of the current collector as the result of the enhanced frequency of random particle collisions and particle contact time with the current collectors. 11,22 Thus, both higher electroactivity toward HER and high surface area of NF likely promoted electrocatalytic activities of the Ni/AC flow cathodes. More positive HER potentials with higher Ni/AC loadings (for NF-Ni/AC and SS-Ni/AC) are likely due to the improved onset potentials for HER since those NF and SS mesh are HER-active current collectors (Figure 1).…”

“…The other study showed the impact of the surface area of the current collector that significantly affected the conductivity of the flow electrode system for electrochemical energy storage. 11 The physicochemical properties of current collectors for Ni/ AC flow cathodes have not been examined but can also be significant in the overall performance of MECs. We hypothesized that different active surface areas and catalytic activities toward the HER by current collectors affect the overall hydrogen production in MECs.…”

“…A current collector is a crucial component in the flow electrode system which is responsible for transferring electric charges to the suspended particles and is a major contributor to the electrical resistivity . However, the interfacial phenomena between current collectors and the suspended particles are often neglected and only a few studies have examined the impacts of the current collector on the electrochemical activities of flow electrodes for various applications. , For example, one study reported anodic flow electrodes based on Ti x O 2 x –1 and carbon black particles coupled with different current collectors (IrRu, IrTa, Pt, and Ti) for mediated oxidation of organic pollutants in water . In that study, the charge transfer resistance and chemical stability of the current collector demonstrated significant impacts on the direct electron transfer (DET) rate in the anodic flow electrode, which impacted the overall energy efficiency of the system.…”

“…In that study, the charge transfer resistance and chemical stability of the current collector demonstrated significant impacts on the direct electron transfer (DET) rate in the anodic flow electrode, which impacted the overall energy efficiency of the system. The other study showed the impact of the surface area of the current collector that significantly affected the conductivity of the flow electrode system for electrochemical energy storage . The physicochemical properties of current collectors for Ni/AC flow cathodes have not been examined but can also be significant in the overall performance of MECs.…”