This PhD project deals with the development of inorganic-polymer composites for positive electrodes of all-solid Li-ion batteries. It will be  developed in collaboration between the laboratories ICMCB-Bordeaux, LCPO-Bordeaux and IPREM-Pau. Mixed conductive polymers will be developed. They will act as an artificial interface between the active LiNi1-x-yMnxCoyO2 or LiFe1 yMnyPO4 positive electrode materials and the ceramic electrolytes (phosphates, oxides or sulphides) to (i) prevent reactivity at the solid-solid interface, but also (ii) bring plasticity to this  interface, essential for all solid state batteries. Indeed, the polymer can functionalize both surfaces. It will ensure the electronic percolation but also, with the ceramic electrolyte, the ionic conduction of Li+  within the massive composite electrode. This project is built on the recognized and highly complementary expertise of the three academic partners and their scientific and technological environments. ICMCB is specialist in the synthesis and characterization of materials for the electrochemical storage of energy, and especially in  materials for batteries, LCPO in the development of new functional polymers for energy and IPREM in the characterization of reactivity to surfaces and interfaces.  It will be essential to characterize the electronic and ionic conduction properties, the stability, as well as the mechanical properties of the polymers and composite materials thus prepared, according to: (i) the composition (nature and concentration  of the different monomers) and the structure of the polymer, (ii) the composition (ratio polymer/electrode material/inorganic electrolyte) and the physico-chemical properties (nature of the interaction: mixing or impregnation and coating or grafting) of the composite material and (iii) the cycling conditions (potential window, type of electrolyte, cycling regime, temperature). The objective will be to demonstrate that this strategy of synthesis of new materials makes possible to lift the reactivity and decohesion locks at the solid-solid electrode-electrolyte interface. ICMCB and LCPO are two neighboring laboratories on the same campus at the University of Bordeaux (less than 500 m away from each other), the PhD candidate will thus have the possibility to perform its research all along the project in both, and he/she will spend at least 3 months as secondment at IPREM in Pau, 2 hours by train from Bordeaux. Short and regular stays will be organized all along the three years at IPREM in order to characterize all the interfaces, in the pristine composite between the inorganic material and the  polymer, but also after cycling. All the fees induced by these travels will be taken in charge by the project.

Supervisor(s) contact:
CROGUENNEC Laurence (ICMCB), laurence.croguennec@icmcb.cnrs.fr
CLOUTET Eric (LCPO), eric.cloutet@enscbp.fr 
OLCHOWKA Jacob (ICMCB), jacob.olchowka@icmcb.cnrs.fr