Liquid is only in contact with the PEEK flow body, gaskets (PTFE, Viton or EPDM) and optical window (UV/VIS transparent quartz glass). Connections to the cell is with 1/4-28 UNF threads and will allow many tube diameters. As standard the cell comes fittings for 1/8 OD hard tubing.

TECHNICAL SPECIFICATIONS:

• SMA 905 fiber optical connection
• Optical path length from 0.05 mm to > 1 cm
• Flow rates > 100 ml/min with minimal pressure loss in the cell (internal hydraulic bypass)
• Full/large pH range – All parts are in corrosion resistant materials (PEEK flow body, PTFE, Viton or EPDM gaskets). Only exception is the optical quartz window which can corrode after prolonged use in glass corrosive media (typically hydroflouric acid and strongly alkaline solutions (e.g. 6 M KOH) and at elevated temperatures. Cell is supplied with replacement optical quartz windows.
• Fittings for tight connecting to 1/8” tubing – For other tube dimensions please make a request
• Gaskets/Spacers Materials: PTFE, EPDM or VITON (comes as standard with spacers for optical lengths from 0.05 mm to 10 mm)

PERFORMANCE

Graph below shows absorbance measured in UV/VIS cell with 0.1 mm optical length on ‘yellow fruit color’ diluted with 1:10.

OTHER RESOURCES

• TO BE UPDATED

SINGLE GASKETS & PACKS OF GASKETS (A, S and X cell): Gasket can be ordered individually, however, we also offer packs of Spacer/Cover gaskets with a volume discount. These pack includes gaskets with thicknesses that will allow testing and compression of almost any electrodes thicknesses. Typically the PTFE Thin Pack will be combined with one of the PTFE, VITON or EPDM Thick Packs.

PTFE Thick Pack includes sets (one pair) of

• 1 set – 0.5 mm PTFE
• 1 set – 1.0 mm PTFE
• 1 set – 2.0 mm PTFE

VITON Thick Pack includes sets (one pair) of

• 1 set – 0.5 mm VITON
• 1 set – 1 mm VITON
• 1 set – 2.0 mm VITON

EPDM Thick Pack includes sets (one pair) of

• 1 set – 0.5 mm EPDM
• 1 set – 1 mm EPDM
• 1 set – 2.0 mm EPDM

GENERAL: Gaskets are supplied in either PTFE, VITON or EPDM. VITON and EPDM is more flexible and will easily seal the cells, however, the minimum thickness of VITON/EPDM gaskets is 0.5 mm. PTFE gaskets are more rigid but comes in thicknesses down to 0.05 mm. Combination of several (both PTFE and Viton) gaskets can be done to ensure right electrode thickness/compression.

PTFE: Overall most corrosion resistant material and comes with thicknesses down to 0.05 mm. But rigid and less good sealing properties

VITON: Compressible that will make cell sealing easy. Redox-Flow recommends VITON (and PTFE) for Vanadium flow battery applications – please see a chemical compatibility chart of VITON for your specific application

EPDM:Compressible that will make cell sealing easy. Redox-Flow recommends EPDM (and PTFE) for alkaline conditions – please see a chemical compatibility chart of EPDM for your specific application

All A, S and X-cells share the Spacer/Cover gaskets and are produced with either 2.5 cm x 2.5 cm and 5 cm x 5 cm active area  – see photo belowSINGLE GASKETS & PACKS OF GASKETS (A, S and X cell):

Gasket can be ordered individually, however, we also offer packs of Spacer/Cover gaskets with a volume discount. These pack includes gaskets with thicknesses that will allow testing and compression of almost any electrodes thicknesses. Typically the PTFE Thin Pack will be combined with one the PTFE, VITON or EPDM Thick Packs.

PTFE Thin Pack includes sets (one pair) of

• 2 sets – 0.05mm PTFE
• 2 sets – 0.1 mm PTFE
• 2 set – 0.25 mm PTFE
• 1 set – 0.5 mm PTFE

PTFE Thick Pack includes sets (one pair) of

• 1 set – 0.5 mm PTFE
• 1 set – 1.0 mm PTFE

VITON Thick Pack includes sets (one pair) of

• 1 set – 0.5 mm VITON
• 1 set – 1 mm VITON

EPDM Thick Pack includes sets (one pair) of

• 1 set – 0.5 mm EPDM
• 1 set – 1 mm EPDM

GENERAL: Gaskets are supplied in either PTFE, VITON or EPDM. VITON and EPDM is more flexible and will easily seal the cells, however, the minimum thickness of VITON/EPDM gaskets is 0.5 mm. PTFE gaskets are more rigid but comes in thicknesses down to 0.05 mm. Combination of several (both PTFE and Viton) gaskets can be done to ensure right electrode thickness/compression.

PTFE: Overall most corrosion resistant material and comes with thicknesses down to 0.05 mm. But rigid and less good sealing properties

VITON: Compressible that will make cell sealing easy. Redox-Flow recommends VITON (and PTFE) for Vanadium flow battery applications – please see a chemical compatibility chart of VITON for your specific application

EPDM:Compressible that will make cell sealing easy. Redox-Flow recommends EPDM (and PTFE) for alkaline conditions – – please see a chemical compatibility chart of EPDM for your specific application

DESCRIPTION:  This is a multi-functional cell intended as an add-on to an flow battery test setup with two fundamental assembly/application principles.

Standard OCV cell : In this assembly the cell can be used for measurement of the OCV and individual cathode and anode overpotentials. I.e. this is is an invaluable tool for flow battery research and optimisation. Drawing below explains the working principles.

Left picture below (click for larger view) show the cell voltage, OCV and the cathode/anode over potential during charging/discharging of the vanadium flow battery cell. Right picture shows the same measurements during measurement of polarisation curve. In this picture also the difference between the cell voltage and the sum of the OCV and overpotential has been included and shows that within experimental precision (1-2 mV) of the equipment used the sum of these voltages equals the cell voltage.

OCV cell with internal reference potential : In this configuration the cell has the same capabilities as the standard OCV cell with the only difference that an additional half cell in the setup allows measurement of all potentials relative to a reference potential. Drawing below explains the working principles.

TECHNICAL SPECIFICATIONS:

• OCV cell with fittings for 1/8” OD tubing – for other diameters please make an inquiry
• Electrolyte only gets in contact with graphite materials and corrosion resistant tubing/fittings
• Gaskets/Spacers: PTFE, EPDM or VITON

OTHER RESOURCES

• Assembly Manual

Some of the unique features of the S-cell Stack are

• Any number of cells between 1 and 9
• Any electrode thickness > 1 mm
• Individual cell voltages can be measured on the bipolar plates

The electrolyte is only in contact with flow block (graphite), spacers (PTFE, Viton or EPDM), O-ring (Viton/EPDM), bipolar plate, electrode and membrane. The S-cell is intended for optimisation studies, but can also be used a normal flow battery test cell like the A-cell.

TECHNICAL SPECIFICATIONS:

• Active Area: 25cm2 (5 cm x 5 cm) – for other dimension, please make a request
• Only works with electrodes > 1 mm
• Body made out of Graphite – for Titanium or other materials, please make a request
• Stainless steel end plates
• Gold plated cobber current collectors
• Swagelok fittings for tight connecting to  1/8” tubing – for other tube dimensions, please make a request
• Gaskets: See materials variations and thicknesses at Gasket/Spacers
• Comes ready-to-use as on pictures but without membranes and electrodes
• Top-performance – With SGL carbon felt and FS950 membrane, polarisation curve gives ASR of 0.8 Ωcm2 per cell – performance is not limited by cell design but limited by electrodes/membranes

OTHER RESOURCES

• S-Cell Stack Assembly Manual

AV Carb G280 Graphite felt – Ready-to-use – It is thermally treated to give optimal catalytic performance – 2.8 mm nominal thickness/uncompressed

AV Carb G475 Graphite felt – Ready-to-use – It is thermally treated to give optimal catalytic performance – 4.7 mm nominal thickness/uncompressed

AV Carb MGL370 Carbon paper – This carbon paper is not PTFE treated, but to get optimal flow battery performance it needs thermal treatment –  0.37 mm nominal thickness/uncompressed

• Size either
  • Precision cut to fill out whole area of graphite/PEEK block (about 10 cm x 10 cm) with four holes for alignment bars
  • 12.5cm x 12.5cm – can be further cut to into 4 pieces of approx. 6.25cm x 6.25cm OR 9 pieces of 4.2cm x 4.2cm that are suitable for both/either the 5cm x 5cm or 2.5cm x 2.5cm active area.
• For other dimensions make an inquiry

The following membranes are available

• Fumatech FAP 450 – anion exchange –  for flow batteries
• Fumatech FAPQ 330 – anion exchange –  for flow batteries
• Fumatech FS-930 – cation exchange –  for flow batteries
• Fumasep FAAM-20 – anion exchange – for alkaline electrolysis
• Fumasep FAAM-PK-75 – anion exchange – for alkaline electrolysis
• Fumasep F-10150-PTFE – cation exchange – for PEM electrolysis

Find more information and datasheets at Fumatech

Some of the unique features of the S-cell are

• Can be operated with or with-out bipolar plates – unlike any other product on the market
• Cell potential can be measured directly on bipolar plates – hereby intrinsic cell performance is measured and does not include contact resistances to current collectors
• Can be connected with Flow Through Electrode Holder (Flow through electrode holder) for e.g. inline monitoring of pH, ORP, reference, conductivity or any other electrode.
• Can be connected the Inline Pressure Unit (Inline pressure unit) for measurement of electrode hydraulic resistance
• Signals from pressure sensors and electrodes can be recorded in AUX Unit (AUX Unit), which combined form an extremely powerful tool for both optimisation studies or flow battery chemistry development.
• The electrolyte is only in contact with flow block (graphite), spacers (PTFE, Viton or EPDM), O-ring (Viton/EPDM), bipolar plate, electrode and membrane.
• Can be converted into a A or X-cell by purchase of A-cell graphite flow body or X-cell PEEK flow body & current collectors. Combined the A, S and X-cells allows virtually testing of any type of electrochemical energy conversion technologies – Flow batteries, Alkaline Water Electrolysis, Anion exchange membrane water electrolysis, Zero Gap electrolysis, PEM water electrolysis, CO2 electrolysis, PEM/Alkaline fuel cells –  that can be operated to high temperatures and in the full pH range

GASKETS & ELECTRODE THICKNESS: Due to the many variations, cells are sold without gaskets and bipolar plates that has needs to be ordered individually.

The overall configuration and variation possibilities are shown in the image below – (Click on picture to get higher resolution)

The S-cell is intended for thick electrodes (> 0.5-1.0 mm), for thinner electrodes the A-cell  is a better option. The active electrode area (either 2.5cm x 2.5cm OR 5cm x 5cm) is determined by the gaskets. I.e. both active areas can be used in the same cell if both types of gaskets are ordered. For the S-cell the following gasket must be ordered individually:

Cover/Spacer gaskets (click on link)

Flow field gaskets (click on link)

To minimize the pressure loss inside the cell it is recommended to use as-thick-as-possible Flow field gaskets and use Cover/Spacer gaskets to adjust the final thickness/compression of the electrode. The final compressed electrode thickness is the sum of the thicknesses of both the Flow field gaskets and Cover/Spacer gaskets, here several gaskets (and materials) and thicknesses can be combined. In our gaskets products we offer packs of different gasket thicknesses, and we recommend these as these will allow you to test virtually any electrode thickness and compression.

The S-cell can be operated without bipolar plates. However, in flow battery optimisation studies it may be important to know the performance in combination with a bipolar plate e.g. to evaluate contact resistances. For this reason we also offer optional bipolar plates (hard graphite/polymer composite), alternatively we can supply you with the 2D drawing if you want to test your own bipolar plate material.

Bipolar plates  (click on link)

PERFORMANCE – Performance tests have shown that area specific resistances down to about 0.60 Ωcm2 can be obtained, i.e. the cell design does have an influence on the intrinsic cell performance.

TECHNICAL SPECIFICATIONS:

• Active Area: 5cm x 5cm OR 2.5cm x 2.5cm – for other dimensions, please make a request
• Electrode thickness > 0.5-1 mm (depending on electrode material and flow rate)
• Stainless steel endplates
• Electrolyte only in contact with graphite body, fittings and gaskets. All made in corrosion resistant materials (from acidic to alkaline)
• Gold plated cobber current collectors
• Swagelok fittings for tight connecting to 1/8” tubing (1/4″ or other fitting sizes on request)
• Gaskets Materials: PFTE, VITON and EPDM  – other materials on request

OTHER RESOURCES

• S-Cell Assembly Manual

Bipolar plate for S-cell and S-cell stack – 1.5 mm thick in Eisenhuth PPG86 material.

Current collector for S-cells and A-cell – Gold plated copper current collector

Current collector for X-cell – Current collectors for the X-cell with and without flow field (Nickel, Titanium, Stainless Steel and Copper) – For other materials please make an inquiry.

Our cells can also be used for other applications than the ones described e.g. CO2 reduction, non-aqueous systems and high temperature that may require special combinations. This could be combination of a graphite half-cell with a titanium half-cell or titanium with nickel. We have not included all these combination as standard products, but send us an inquiry and we will let you know what is possible.

If you write an inquiry, we are always interested in knowing your application, so share this if you can.