Slurry electrodes solve both problems: flowable suspensions of electronically conductive particles enable continuous electrodeposition and double layer charging. The suspended particles can subsequently be advected away with the deposited solid phases – and similarly advect capacitively adsorbed charge.
Controlling the residence time of the electrode allows modulation between orthogonal current sources: either primarily capacitive or faradaic current draw. In the capacitive regime, current draw from the double layer is unimpeded by faradaic mass transfer limits. As the capacitively charged electrode flows out of the cell, its stored surface charge drives reactions during equilibration—decoupling charge loading and reaction timescales.
Here, we establish dimensionless operational and design criteria required to exploit this separation of reactive and capacitive timescales to allow continuous current draw beyond reactive rate limits. We leverage a 1D transient electrochemical model to resolve capacitive, faradaic, and mass transport timescales, providing critical insight into power-density implications of each operating regime on cell-level performance for energy storage applications, but also the extent to which a reaction can be driven outside the electrochemical reactor. Ultimately, we propose design strategies that bypass reactive rate limitations by "electrochemical-looping", whereby charge is loaded onto the double layer in the electrochemical cell and a faradaic reaction is driven by the discharge of the double layer outside the cell. This separation of charge loading unlocks high-rate operation of electrochemical reactors utilizing sluggish chemistries -- overcoming rate limitations in critical sectors such as chemical synthesis and grid-scale storage.