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ENERGY STORAGE HEROES: MICHEL ARMAND

eralization of Nernst equation in the
solid-state, to predict the variation
of the voltage with stoichiometry, a
model that has remained indisputable.
Also, a wealth of intercalation com-
pounds, many new, had been screened
electrochemically. This work also con-
tained the first mention that intercala-
tion compounds could be used both at
the positive and negative electrodes —
defining the Li-ion battery principle.
Around this time Armand and his
collaborators filed a patent through
the CNRS which ended up in a long
litigation with the US Patent Office,
due to an unknown premature disclo-
sure. Nevertheless, it prompted a joint
research project between the CNRS,
the French oil company Elf-Aquitaine,
and Canadian electricity utility Hy-
dro-Québec, aimed at designing ulti-
mately a lithium-polymer battery for
electric vehicles.
Armand was in charge of the scien-
tific orientations, to be materialized
with Michel Gauthier, head of the cor-
responding research group at Hydro-
Québec.
This patent contained the first spe-
cific mention of the use of graphite
negative electrodes, as polymers do
not co-intercalate in graphite like
most liquid solvents do. “I later sug-
gested to a PhD student, Rachid Yaza-
mi, to include this work in his thesis,”
says Armand. “The proof being given
by X-rays to the formation of LiC6.”
Around this time he met Maryse
Cirera, who was working for Motoro- Armand’s identity card while studying at the Ecole Normale Supérieure at
la in Grenoble. They married and later Saint-Cloud
a daughter, Caroline, was born. “She
is now a perfume specialist, from her
childhood passion for fragrances,” he TFSI) for liquid and polymer electro- as supporting electrolyte for batter-
says. “It’s another more pleasant side lytes. ies, photo-electrochemical solar cells,
of chemistry in our family.” Salts of these anions are produced light-emitting diodes and antistatics.
In 1982 Armand was invited to be a now on a large scale as solutes for liq- “But the collaboration between the
visiting scientist at Lawrence Berkeley uid and polymer electrolytes, but are state agency and industrial companies
Laboratory. He would go back regu- also the most used, by far, ingredient failed because the CNRS had ceded
larly two months every summer for of ionic liquids. These new materials the property of the patent to Elf-Aqui-
the next six years. draw considerable attention as they taine, who offered them to Japan’s
The company Polyplus was then have conductivities comparable to Yuasa, in 1986. Hydro-Québec used
created in California for batteries us- that of aqueous solutions, an extreme- its pre-emptive rights but was forced
ing the then novel concept of S–S re- ly wide range of temperature (400°C), into a collaboration with Yuasa.
versible redox bond cleavage, i.e. a where they are stable liquids with no In 1995, Michel Armand moved to
polymerization-depolymerization of a vapour pressure (non-flammability). the Université de Montréal’s Depart-
high polymer (dimercaptothiadazole), They find use as green solvents in ment of Chemistry to be closer to the
predating by 20 years the interest in which a wealth of chemical reac- development team at Hydro-Québec,
LiS batteries we see today. tions can be accomplished without and to its manufacturing arm cre-
Independently, within the CNRS/ resorting to volatile organic solvents; ated for this purpose, Argotech. The
Hydro-Québec/Elf collaboration, 30
patents were filed between 1980 and
1986, including the introduction of In recent developments, Armand was involved in
new families of highly conductive, the co-discovery of metal fluorosulfates LiFeSO4F
ultra-low lattice energy salts (per-
fluoroimides such as [FSO ) N ] and as possible improvements over phosphate positive
2 2
[CF SO ) N], respectively FSI and electrodes.
3 2 2
www.energystoragejournal.com Energy Storage Journal • Summer 2019 • 63