Battery and supercapacitors Test

(Update march 01 st 2023)

Person in charge

Camille DOUARD (supercapacitors, Chantrerie site)

Patrick SOUDAN (batteries, Lombarderie site)

It is within the "Electrochemical storage and conversion of energy" (ST2E) group that research in the field of batteries and supercapacitors is conducted at IMN.

Equipment for electrochemical tests :

The study of lithium batteries requires the use of specific equipment due to the sensitivity to air and humidity of their constituents such as the electrode materials, the non-aqueous electrolytes and the metallic lithium.

Some studies in the field of supercapacitors also require the use of a controlled atmosphere (ionic liquids, metal-ion capacitors...). However, a large part of the activities is carried out under air, in aqueous media.

We therefore have special devices dedicated to the assembly and testing of these various storage systems, alongside equipment for the synthesis and analysis of materials (mills, mixers, ovens, vacuum ovens, spectrometers ...).

Electrochemical cells

We have many models of electrochemical cells.

Among these, the oldest but still widely used are “Swagelok” laboratory prototypes with 2 electrodes, diameter ½ inch (12.7 mm). These stainless steel sealed cells are equipped with interchangeable pistons made of metals suitable for the different electrode materials studied (aluminum, stainless steel, nickel...). These cells are particularly suitable for experiments such as galvanostatic cycling, cyclic voltammetry, etc...

“Swagelok” laboratory prototype

For impedance measurements, for which it is preferable to have a third electrode as a reference electrode, we have three-electrode cells specially designed and manufactured on site, with a diameter of 25 mm.

The cells used for the study of supercapacitors vary according to the cycling conditions (2 or 3 electrodes, electrolyte, format of the electrode to be tested).

Special cells are also available for in situ or operando experiments, such as X-ray diffraction, tomography, X-ray absorption spectroscopy...

We also manufacture more commercial formats such as button cells and pouch cells.

Finally, we also use glass cells, especially for the study of electrodes in aqueous media.

« flat cell » for flat samples (thin films) tested in a 3 electrodes configuration

Different electrochemical cells:

from left to right :

- “Swagelok” with 2 electrodes (12.7 mm)

- “Swagelok" with 3 electrodes (25 mm)

- Operando cell

- Button battery CR2032 (opened)

« pouch-cell »

-Glove box

Six glove boxes under purified argon from Jacomex and MBraun are dedicated to the fabrication of different types of batteries (see below) or the synthesis and analysis of materials in an airtight environment. They are also equipped with external electrical connections to perform electrochemical tests in a glove box.

Different types of batteries:

Electrochemical laboratory cells (“Swagelok” or El-Cell type) with 2, 3 or 4 electrodes
Button cells (CR20XX): 3 presses in glove boxes which allow the crimping of button cells as well as their opening for post-mortem analysis of their constituents (electrodes, electrolyte, separator...)
Pouch cells, which are flat batteries widely used in industry and in commerce
A glove box is dedicated to batteries in aqueous media (wet argon)
A glove box is dedicated to batteries based on organic materials
A glove box is dedicated to the activity related to supercapacitors

A glove box dedicated to the activity related to supercapacitors

Dry argon glove box with presses for button cells and pouch cells.

Dry argon glove box (for lithium batteries including lithium metal), with battery cycler for electrochemical cell cycling in glove box

-Potentiostats / galvanostats (cyclers)

A range of different types of potentiostats/galvanostats, representing a total of more than 350 channels, is available to implement all electrochemical techniques (within the limits of 20 V - 400 mA). Some channels allow low current cycling (~ µA), others allow cycling of devices up to 10A.

The most commonly used techniques for the study of devices (batteries and supercapacitors) are galvanostatic cycling (charge-discharge cycles), cyclic voltammetry, pulse methods (PITT, GITT...) and impedance spectroscopy (EIS).

We find in this park:
     * 6 VMP3 (Bio-Logic), i.e. 91 channels, for currents up to 400 mA
     * 1 VMP2 (Bio-Logic), i.e. 16 channels, for currents up to 400 mA
     * 11 MPG2 (Bio-Logic), i.e. 176 channels, for currents up to 100 mA
     * 5 VMP1 (Bio-Logic), i.e. 80 channels, for currents up to 10 mA, including 8 channels equipped with a current amplifier (VMP 2A) up to 2 A
     *Transportable 1 or 2 channel models: 2 SP50, 2 SP150, 1 SP200, 1 SP300; 1 VSP and 1 VSP300 (Bio-Logic)

In addition, we have 32 channels allowing impedance measurements in a wide frequency range from 10 µHz to 7 MHz.

Différent cyclers : MPG2 et VMP1 (Bio-Logic) on the left, VMP3 (Bio-Logic) on the right

Cycler (MPG2 from Bio-Logic), with button batteries and "Swagelok" cells with 2 and 3 electrodes.

-Ovens and climatic chambers:

9 thermostatic chambers (Memmert, Binder, Thermo, MMM Medcenter) for temperature cycling (-40 to +180°C)

Cyclers and ovens for température cycling

Pouch-cells, cycler (VMP3), climatic chamber and oven for cycling at different temperatures

Results Examples

Cycling of a complete battery at room temperature (button cell). Composition of the negative electrode: Silicon/Graphite/Graphene/polyacrylic acid/lithium polyacrylate 43:43:4:8.5:1.5. Composition of the positive electrode: LiNi0.5Mn0.3Co0.2O2/Carbon black/PVdF 96:2.2:1.8. Mass loading of the positive electrode 25 mg/cm². Areal capacity of the positive electrode 4.2 mAh/cm². Mass loading of the negative electrode 3.3 mg/cm². Areal capacity of the positive electrode 6 mAh/cm². Liquid electrolyte based on LiPF6.

These results were acquired by J. Xiong during her thesis, in the framework of the ANR SILMARILION project. The positive electrode has been defined in the ANR PEPITE project.

Organic electrode: charge-discharge curves of a Mg(Li2)-p-DHT//Li cell (left) and evolution of the specific capacity and coulombic efficiency as a function of the number of cycles

(a) Cyclability of complete cells based on 4-hydroxy TEMPO benzoate (positive) and a viologen-naphatlenediimide di-block oligomer (negative) in an aqueouselectrolytecontaining NaClO4 (8M); glass cell (red) and pocketcell (purple),

(b) corresponding Ragone curves. The electrodescontain about 80 mg/cm2 of active material for a thickness close to one millimeter.