The design of the X-cell stack is a result of almost 10 years of know-how in the field of flow redox chemistry and maybe the only research stack product on the market. It was developed for testing/optimisation of components (electrode/membranes/bipolar plates), testing of stack properties, upscaling and demonstration. It can be tested with cells up to nine cells, electrodes must be at least 1 mm thick, but can be any material. Different electrode compressions can be obtained by different spacer thicknesses. Stack can be is supplied with different bipolar plate materials (Nickel, Titanium, Stainless Steel). Design has been with focus on trade-of between minimizing pressure inside cell and keeping shunt currents low.
Some of the unique features of the S-cell Stack are
- Up to 9 cells in the stack
- Any electrode thickness > 1 mm
- Individual cell voltages can be measured on the bipolar plates
The electrolyte is only in contact with flow body (PEEK), gaskets (PTFE, Viton or EPDM), O-ring (Viton/EPDM), metal bipolar plate, electrode and membrane. The X-cell is intended for general electrolysers purposes ranging from acidic to alkaline environment.
TECHNICAL SPECIFICATIONS:
- Active Area: 25cm2 (5 cm x 5 cm) – for other dimensions, please make a request
- Bipolar plates either Nickel, Titanium or Stainless Steel
- Electrode thicknesses > 1 mm
- Flowbody made in PEEK
- Stainless steel end plates
- Swagelok fittings for tight connecting to 1/8” tubing – for other tube dimensions, please make a request
- Comes ready-to-use as on pictures but without membranes and electrodes
PERFORMANCE DATA
Figure below shows data for the stack in ‘alkaline electrolyser’ mode with 6 cells. I.e. with 6 M KOH and nickel foam electrodes and operated at room temperature. Here an area specific area resistance (ASR) of 1.2 Ωcm2 is obtained. This value is similar to the best performance in scientific literature for single cell under similar conditions. Thus performance can be greatly improved by optimised separators, electrode catalysts and higher temperatures. More importantly the figure also shows the faradaic efficiency which increases from about 90 % at 10 mA/cm2 to almost 100 % faradaic efficiency >50 mA/cm2 . This excellent performance is a result of carefully designed flow field channels in the stack that minimizes shunt currents between cells. General prediction of shunt currents are extremely difficult, nonetheless if the ASR is improved/minimized this will lead to lower shunt currents and higher faradaic efficiency. Considering that the data shown are for un-optimised electrodes the faradaic efficiency can be considered as a minimum value for this configuration.
Together with the flexibility and versatility, we consider our stack as the best platform for testing of stack properties, upscaling and demonstration. We made the platform, you optimise it.
Figure below shows individual cell voltages when the stack is operated with 40 mA/cm2 and it is seen that the end cells have slightly higher voltages than the central cells. It is anticipated that this trend is related to shunt currents that are higher for the central cells.
OTHER RESOURCES
- TO BE UPDATED
