Our planet faces formidable sustainability challenges that call for rigorous and relevant research on various disciplines which include, among others, the field of electrochemical energy storage. Batteries have become essential in tackling global warming and energy security. Rechargeable Li-ion batteries, by having the highest energy density of any such device, have conquered the electronics field and are regarded as the technology of choice for powering electric vehicles with great hope that they could enter the field of load-leveling for mass storage of renewable energy. For such foreseen applications to materialize, new advances in performances/safety/costs are required. More specifically, known intercalation electrode materials must be understood or new ones relying on new concepts must be explored to ensure a leap forward in performance.
Classical positive electrodes for Li-ion technology operate mainly via an insertion-deinsertion redox process involving cationic species. This is not any longer true as we recently demonstrated, via a patented game changing chemical approach, the redox activity of the anionic network with the reversible formation of peroxo groups (2 O2- --> (O2)2-) which was postulated but never experimentally proved, thus explaining the staggering capacities (280 mAh/g) reported for the Li-rich layered Li(Li0.2NixMnyCoz)O2 phases termed as Li-rich NMC phases. This capacity increase would translate to a 20 to 25% improvement in present battery autonomy. Rapidly, BASF, 3M and others were eager to commercialize such materials. Yet, they met many difficulties such as a drop in the batteries’ average potential across charge-discharge cycles that deterred their commercialization. By exploring new chemistries deviating from the classical approach and calling for the use of 4d-metals, we could obtain new phases exhibiting similar capacities to those of the Li-rich NMC but with no potential fading upon cycling.
In light of the above, the objectives of DeLi-RedOx are to i) exploit further this new concept associated with the redox activity of the anionic network which provides myriad opportunities, with the feasibility of using 4d metals, to search for new high capacity electrodes and ii) eagerly explore our proposed scenario for combating capacity fading which reinvigorates the search for proper materials formulations that eliminate the voltage decay, both of which should enable all the advantages of this new class of high capacity electrodes based on dual cationic and anionic redox mechanisms to be harvested. This calls for a combination of fundamental science enlisting creative chemical designs and well thought modelling approaches, and state of the art characterization techniques together with cell construction and testing.
To achieve these goals, we have assembled a consortium uniting partners from Collège de France (FRE3677-Chimie du Solide et Energie and Laboratoire de Chimie de la Matière Condensée de Paris LCMCP), Institut de Recherche de Chimie Paris (IRCP), ICG (Montpellier), IPREM (Pau) and LRCS (Amiens) having great experience of working together and complementary expertise in synthesis, crystal chemistry, modelling, and electrochemistry testing. These laboratories belong to the French Research and Technology National Network on Electrochemical Energy Storage (RS2E), whose goal is to ensure a continuum from research to development via prototyping and then to a quick transfer to our industries so as to benchmark optimum electrode formulations into practical Li-ion batteries.
Madame Gwenaelle Rousse (Chimie du Solide et de l'Energie, Collège de France)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
LCMCP Chimie de la Matière Condensée de Paris
IPREM Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux
IRCP Institut de Recherche de Chimie Paris
ICG Institut Charles Gerhardt
FRE 3677 Chimie du Solide et de l'Energie, Collège de France
LRCS Laboratoire de Réactivité et Chimie du Solide
Help of the ANR 494,688 euros
Beginning and duration of the scientific project: September 2014 - 48 Months