Highly conductive colloidal carbon based suspension for flow-assisted electrochemical systems

Abstract

Fluid and highly conductive carbon-based suspensions are reported The suspensions are potentially useful for flowassisted electrochemical applications Charge and discharge of flowable electrodes is quantitatively demonstrated

Experimental Study of Electronic and Ionic Conductivity of a Carbon-Based Slurry Electrode Used in Advanced Electrochemical Energy Systems

“…After reaching a maximum value under flowing conditions, the conductivity starts to decrease by a further increase in the flow rate. This trend was also observed in previous studies conducted by Alfonso et al 43 and Halfon and Suss. 45 As the particles start to move, the partially-sedimented layer and the developed connection network between the particles are disturbed.…”

“…These aspects have been barely studied in the literature, particularly in the context of carbon slurry electrode applications for power/energy systems. Several relatively recent studies looked at the dispersion of CB and Ketjenblack at different concentrations for electrochemical flow capacitor applications. ,− Other recent studies also indicated that charging–discharging of slurry electrode particles mainly depend on particle-to-current collectors and interparticle contacts that form a bridging percolation network to conduct electrons. Charge storage in the slurry electrode can be achieved through intercalation, electric double-layer capacitors formation, ,, or an electrochemical surface redox reaction .…”

“…34 Most of these studies reported that increased mass loadings can make the slurry too viscous, making it difficult to flow properly, which offsets the benefit offered by the increase in mass loading. 26,43,44 Different types and concentrations of carbon slurry electrodes, with various viscosities, have also been reported before: 8 Pa s for 15 wt % carbon by Porada et al, 44,45 Pa s for 9 wt % Ketjenblack by Alfonso et al, 2,43 Pa s for 10 wt % highly monodispersed carbon beads by Presser et al, 1,12 and Pa s for carbon particles at 23 wt % concentration by Campos et al 5 Therefore, shear-thinning behavior of carbon-based slurry leads to a significant increase in pressure drop at low flow rates and high carbon mass loadings. 19 Thus, it is crucial to keep slurry flowing at the maximum possible mass loading to attain higher charge transfer (or electrical conductivity) of the slurry, while minimizing pumping energy through the optimum flow rate and efficient channel design.…”

Electronical Conductivity Improvement of Carbon-Based Slurry Electrodes Using Carbon Foams for Enhanced Performance in Advanced Electrochemical Energy Storage Systems

“…They later studied the collision frequency and contact time of charged and uncharged particles of a slurry electrode; particles are charged after colliding with the CC, and then those charged particles act as CCs for uncharged particles . While increasing the slurry concentration improves its conductivity, it comes with challenges associated with its flowability , (i.e., increasing pumping power) and its long-term stability. ,,, In other words, it is difficult to maintain continuous slurry flow and reasonable pressure drop in flow channels to uphold the required rheological properties of a slurry in slurry systems with high mass loadings …”

“…The interconnected porous structure could also increase active sites for charge transfer and maximize CC's surface area. 36 Many studies have theoretically and experimentally investigated slurry electrode systems' ionic and electronic conductivities, 1,3,[19][20][21][22][23]40,41,46 and some studies have been conducted to measure the electrical conductivity of CFs separately. 37−39,42−44 However, to the best of the authors' knowledge, no research or measured data have been reported in the literature on conductivity enhancement of slurry electrodes after adding CFs.…”