Scientific activities, education, network

Activity in group 2 consists in applying a Solid-State-Chemistry strategy to materials for Li or Na batteries and related compounds.

Activity in group 2 consists in applying a Solid-State-Chemistry strategy to materials for Li or Na batteries and related compounds. Investigations are focused on Li and Na transition metal oxides, on compounds with polyanionic framework, on electronically conductive cobalt oxides and on thin film materials for microbatteries.

Cellules test de batteries au Li dans une enceinte thermostatée / Li battery test cells in controlled temperature cabinet
Cellules test de batteries au Li dans une enceinte thermostatée / Li battery test cells in controlled temperature cabinet

In addition to more « classical » structural and physical characterizations available at ICMCB or via large infrastructures (in particular in situ or operando X-ray and neutron diffraction and XAS), the group has specially developed electrochemical characterizations, X-ray diffraction (in particular in situ or operando), electron microscopy, as well as NMR applied to paramagnetic compounds, with a theoretical approach aiming at better understanding the latter.

The group therefore globally aims at better understanding the materials and their alkali-metal insertion/deinsertion properties, in order to focus investigations on preparing ever better materials in terms of electrochemical energy storage or of remarkable properties.

Some representative research work over the 2009-2014 period:

  • Synthesis of new metastable NaxCoO2 and NaxVO2 by electrochemical deintercalation – polymorphism and vanadium clustering in NaxVO2
  • New AMPO4X (A = H, Li ; M = Fe, V, Mn, Ti ; Y = OH, O, F) Tavorite – structure materials as Li-battery electrodes: broad variety of compositions and broad voltage range (from 1.4 to 4.3 V vs Li+/Li) ; model compounds for analyzing the chemical bond by combining NMR with theoretical calculations
  • New nanometer-scale HxLiyCo3-δO4.zH2O spinel-type compounds : electronic conductors additives and electrode materials for (faradic) aqueous supercaps
  • A broad variety of electrode materials as thin films for microbatteries: Si and Ge alloys as negative electrodes for Li-ion microbatteries for microelectronics ; CuO and FeS2 as positive electrode materials for high capacity Li microbatteries
  • Elucidating redox and phase-change mechanisms occurring during deintercalation and intercalation of Li+ or Na+ ions from AxMO2 (A = Li, Na) layered oxides ; first evidence of reversible participation of oxide anions in the redox process in « HE-NMC » (Li and Mn rich layered oxides)
  • First evidence of a memory effect during cycling of thin film LixSi(Ge) alloys
  • Determining Li, P and H NMR shifts in oxides and/or phosphates studied as electrode materials for batteries, and improving the methodology for DFT modeling of the mechanisms for the contact interaction governing these shifts.

Main networking and partnership

  • Founder and active member of the Alistore and RS2E (associated to STORE-EX Labex) networks; broad academic cooperation in these frameworks.
  • Participation in several ANR projects (Blanc, JCJC, Thematic, Défi DESCARTES)…
  • Creation of a CNRS-CEA common research team for the 2D Microbatteries thematic (detachment of a CEA researcher)
  • Partnership with CEA Tech Aquitaine, LETI-Grenoble et LITEN-Grenoble
  • Partnership with ST Microelectronics
  • Partnership with Toyota Motor Europe

 

Implication in teaching activites