Applications

Non-enzymatic ethanol sensor based on a nanostructured disposable screen-printed electrode.

Automatic sample handling and analysis is very convenient for routine measurements on large number of samples. Metrohm offers a wide range of high performance liquid handling devices that can be combined with the Autolab product range and can be directly controlled by the NOVA software.

The Metrohm 800 Dosino is the workhorse of any automated liquid handling setup. This instrument can be conveniently used in combination with the NOVA software and integrated conveniently with electrochemical measurements performed with the Autolab systems.

The Metrohm 858 Professional Sample Processor is a robotic liquid handling system capable of handling large series of samples automatically. This instrument provides a platform that can be directly controlled by the NOVA software and combined with the Autolab potentiostat/galvanostat for automated high-throughput electrochemical measurements.

A nickel metal hydride battery, abbreviated NiMH, is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but, for the anode, instead of cadmium, it has a hydrogen absorbing alloy. Like in NiCd batteries, nickel is the cathode. The voltage output of such packs is directly proportional to the number of single cells in the pack. In some cases, the total voltage can exceed the maximum of 10 V that is measurable by the Autolab potentiostat/galvanostat. To apply and measure voltages greater than 10 V, we have developed a voltage multiplier that increases the voltage range of the Autolab.

Lithium-ion (Li-ion) batteries are one of the most important energy storage devices in the market. A typical Li-ion battery is usually composed of one or more cells. Characterization of Li-ion cells and batteries usually involves the galvanostatic charge and discharge during various cycles.

This Application Note shows how AUTOLAB and NOVA is used to perform GITT tests on a Li-ion battery. Here,galvanostatic charge pulses are applied, each followed by relaxation time, until the upper potential limit is reached. Then, discharge pulses are applied, followed by equilibration time, until the lower potential limit is reached. From the potential vs. time plot, important information for calculating the diffusion coefficient and thermodynamics parameters quantities can be obtained.

During charge and discharge of a Li-ion battery, lithium ions are transported from one electrode through the electrolyte to the other electrode. Knowing the chemical diffusion coefficient of electrode materials is crucial. The potentiostatic intermittent titration technique (PITT) is one of the most used techniques to retrieve insights on the diffusion coefficient of the electrode active materials.

The main components of a battery are the positive and negative electrodes, together with the electrolyte, which provides only the ionic conductivity. The most common electrolytes are in the liquid state. Therefore, a separator is needed to provide a physical separation between the electrodes. The separator is soaked with electrolyte. The MacMullin number is a parameter used to determine the quality of a separator, in terms of ionic conductivity, when soaked with an electrolyte. The MacMullin number can be calculated, using the results of data fitting of two EIS experiments and the geometric factors of the measurement cells. In this application note, a commercial electrolyte is employed, together with a porous filter, used as a separator.

The TSC SW closed and TSC battery cells are compact systems designed for measurement of air or moisture sensitive materials, such as those materials used in rechargeable batteries. These cells offer well-controlled environment for the in-temperature measurement of solid and gel like materials in contact with metal electrodes in planar geometry. For example, battery active materials, ionically conductive solid-state electrolytes and battery separators can be tested using these cells. In this experiment, standard resistors of 100 Ω are used in both cells to understand the cell effects, if any, on the measurements.