Static Capacitive Deionization (CDI) Test Cell Stack, CSCDITCS

For a static (batch) CDI test cell stack, the design shifts away from a continuous flow loop and instead focuses on a sealed, compact assembly where the electrolyte is either stationary or recirculated within a fixed volume. This configuration is primarily used for fundamental material screening, where researchers need to determine the maximum Specific Adsorption Capacity (SAC) of a new electrode material without the complexity of constant-flow kinetics.

In a static stack, multiple electrode pairs are often layered to increase the total surface area and total salt removal from a small, fixed volume of liquid. The stacking sequence of bipolar plate can be "Current Collector → Electrode → Spacer → Electrode → Current Collector).

Compared to flow mode, the static mode has following advantages: (1) Low Sample Volume: Ideal if you are synthesizing expensive or small quantities of novel nanomaterials (e.g., specific MXenes or doped carbons). (2) Simplified Monitoring: You can measure the initial and final concentration (via conductivity or ICP-OES) without needing high-resolution real-time flow-through sensors. (3) Equilibrium Testing: Easier to reach a true thermodynamic equilibrium between the ions in solution and the ions adsorbed on the electrode surface.

References:

1. J. J. Lado, et al., Performance analysis of a capacitive deionization stack for brackish water desalination, Desalination, 2021, 501, 114912. 

2. L. Xu, et al. Membrane-Current Collector-Based Flow-Electrode Capacitive Deionization System: A Novel Stack Configuration for Scale-Up Desalination, Environ. Sci. Technol. 2021, 55, 19, 13286–13296.