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Materials and composites for electrodes of lithium batteries
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Leader for this research topic: Dr.
Bernard LESTRIEZ (MC)
People involved in the research topic:
Dr. D. Guyomard (DR), Dr. J. Gaubicher (CR),
Dr. P. Moreau
(MC), Dr. P. Soudan (IE), Dr. A-C. Gaillot
(MC)
Post-doc, PhD students, Masters ( 2007-2008) : Dr. P.
Mongondry, Dr. N. Boscher, W. Porcher, C. Fongy, A. Boisard,
S. Desaever, S. Pedneault, K.A. Sied.
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Figure 1: Zoom of a composite electrode for a lithium ion battery showing and active material grain surrounded by the conducting agent (CB) particles and the binder. In the battery, the porosity is filled with the liquid electrolyte. |
Electrodes for lithium batteries are composite
materials obtained by mixing together the active material
(AM) grains with non-electroactive additives such as carbon
black (CB) and a polymeric binder (B). This very complex
medium needs to possess mixed conductivity with both Li+ ionic and electronic conductivity in order to bring efficiently the ionic reactants and the electrons to the surface of each active material (AM) grains. To improve the energy and power density as well as cycle life of lithium batteries, the composite electrode design is important. It means the optimization of the composition of the non-electroactive additives, i.e. selection of the binder and conducting agent combinations, and the tailoring of the processing conditions of the electrode slurry, i.e. selection of the mixing apparatus and conditions, optimization of the solid loading, optimization of the solvent properties, optimization of the tape casting conditions and so on. From the scientific point of view, it is an exciting multidisciplinary research area at the cross-roads of several fields, i.e. the solid-state electrochemistry, and the solid/liquid dispersions and the polymer sciences. |
Thus, the general goal of our studies is to gain a better understanding of the relationships between: the positive or the negative electrode composition, the processing, the morphology, and the resulting electrochemical properties. To achieve this goal:
- The solid/liquid electrode dispersions (slurries) are characterized by a combination of techniques such as low angle laser light scattering (laser granulometry for particle size distribution), zeta potential measurements (surface charging of the particles), rheology and rheomicroscopy (flow properties as well as suspension morphology) (Figure 2).
- The dried composite electrode architectures are characterized by scanning (Figure 1) and transmission electronic microscopes, infra-red and raman spectroscopy, BET surface measurements.
- Electrical and mechanical properties are measured using impedance spectroscopy, large band dielectric spectroscopy (collaboration with J-C. Badot), and mechanical testing machines.
- The electrochemical performance are measured with Two-electrode SwagelokTM test cells and monitored Cell cycling was performed at 20 °C, monitored by VMPTM system in galvanostatic or potentiostatic modes (Figure 3).
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Figure 2 – Flow curve of an electrode
slurry and optical micrographs showing a flocculated structure
at rest that is broken down upon the application of a
shear stress.
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Fig. 3 – Voltage profiles (discharge-charge) versus lithium composition at 2nd, 10th and 50th cycles and Discharge capacity vs. cycle number, for a cell made with a composite (80wt% Li1.1V3O8 12wt% CB 8wt% PMMA) electrodes elaborated with ethyl acetate at a concentration of 0.0025 ml mg-1 with ball milling for 1h at 500 rpm, and an ethylene carbonate concentration of 25wt% before liquid electrolyte impregnation. We used a standard galvanostatic procedure corresponding to the insertion of one lithium ion in 2.5 h during the discharge and one lithium during 5 h during the charge.
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Publications |
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GUY D., LESTRIEZ B., GUYOMARD D.
New composite electrode architecture and improved battery performance from the smart use of polymers and their properties,
ADV. MATER. 2004, 16 N°6, 553-557
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GUY D., LESTRIEZ B., BOUCHET R., GAUDEFROY V., GUYOMARD D.,
Tailoring the Binder of Composite Electrode for Battery Performance Optimization,
ELECTROCHEM. SOLID-STATE LETT. 2005, 8(1), A17-A21
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GUY D., LESTRIEZ B., BOUCHET R. GUYOMARD D.
Critical role of polymeric binders on the electronic transport properties of composites electrode
J. ELECTROCHEM. SOC. 2006, 153(4), A679-A688
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LIGNEEL E., LESTRIEZ B., HUDHOMME A., GUYOMARD D.
Effects of the solvent concentration (solid loading) on the processing and properties of the Composite Electrode
J. ELECTROCHEM. SOC. 2007 153 A235-A241
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LIGNEEL E., LESTRIEZ B., HUDHOMME A., GUYOMARD D.
On the origin of the pre-plasticizer effect of the composite electrode for lithium batteries
Electrochemical and Solid-State Letter. 2007 10 A122-A126
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LESTRIEZ B., BAHRI S., SANDU I., ROUE L., GUYOMARD D.
On the binding mechanism of CMC in Si negative electrodes for Li-Ion batteries
Electrochemistry Communications 2007 9 2801-2806
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| Book chapters |
| Lestriez B, Ligneel E, Guy D, Guyomard D (2007) "Improved Li-ion batteries from tailored processing and binders." In: Zhang SS (ed) Advanced Materials and Methods for Lithium-Ion Batteries. Transworld Research Network, chapter 10. |
| Patents |
Matériau pour électrode composite, procédé pour sa préparation,
D. Guyomard, D. Guy, B. Lestriez, J. Gaubicher et M. Deschamps,
Demande de brevet français CNRS-BATSCAP n°0302891 du 07-03-2003, publiée sous le n° FR 2 852 148. Demande de brevet PCT/FR04/009529 pour extension internationale tous pays, déposée le 5-03-04, publiée le 23/09/2004 sous le n° WO 2004/082047. |
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Last updated, march, 17, 2008
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