Available Equipmentrhd instruments offers a fully-equipped laboratory with the following features
- Fume-hood for safe handling of volatile substances
- Argon glove-box for handling air- and moisture sensitive samples
- Samples can be stored refrigerated in the glove-box
- The full sortiment of rhd measuring cell and setup solutions
- Handling of every sample typ, e.g. liquid, solid or polymers
- Temperature Range -40 °C - 100 °C (Microcell HC) and -30 °C - 250 °C (CompreDrive)
- Stack pressure of up to 1.6 GPa (CompreCell 6C + CompreDrive)
- Option for high-temperature measurements
- Metrohm Autolab and Bio-Logic Potentiostats/Galvanostats & Impedance Analyzer
- dc-voltage range: -10 V - +10 V
- Maximum Current: 2 A
- Frequency Range: 7 MHz - 10 µHz
- Max. ac-amplitude: 350 mV (rms)
- Struers Polishing & Lapping machine
Determination of the dc-ion-conductivty of liquid, polymeric, and solid conductors
Based on you individual requirements, we could perform impedance measurements (2-electrode configuration) for your samples to determine the dc-ion conductivity or the total conductivity for mixed conductors. The sample temperature can be adjusted to values ranging from -40 °C to +100 °C in case of liquid samples and -30 °C to +250 °C in case of polymeric and solid samples (powders or pellets). When using the CompreDrive, the stack pressure can also be (re-)adjusted and monitored, to find the optimal stack pressure value for an optimized contact resistance between sample and current collector electrode.
In case of liquid samples, 1 ml per measurement is required. In case of polymeric or solid samples, disc-like, plane parallel specimens with a diameter less than 12 mm would be perfect, if the Microcell HC setup in combination with the TSC battery cell should be used. When combining the CompreCells with the CompreDrive setup to perform the measurements, also solid electrolyte powders can be measured. Here, only a few milligram are needed.
On demand, a report will be created containing detailled information about the experimental procedure and an overview of the resulting values including a statistical treatment if applicable.
Determination of the MacMullin-Number
The MacMullin number is a measure for the reduction of the ion-conductivity of an electrolyte-wetted separator material compared to the non-confined electrolyte. It is a function of the separator material's tortuosity and porosity
For a typical service measurement of this type you provide us with the separator materials and/or electrolyte solutions that should be used. Depending on your outline we will then perform measurements of both the neat electrolyte and the separator wetted with the same electrolyte. The measurements can be performed at multiple temperatures and with variable number of separators stacked on top of each other. From the relation between neat electrolyte conductivty and separator conductivity the MacMullin number is calculated.