Molecular modeling of polymer-electrolyte interfaces in hybrid-solid battery applications

Lithium-ion batteries are today the most interesting solution to answer the ever-increasing demand for electrochemical energy storage devices. The two main requirements for such systems are a higher gravimetric capacity and an increased safety, both can be solved using a solid electrolyte instead of the liquid ones in the current technology. At present time three main groups of solid electrolytes exist: polymers, inorganic materials, and hybrid materials (a mixture of an inorganic and an organic phase). Hybrids are promising as they combine the high ionic conductivity of inorganic electrolytes and better mechanical properties and processing of polymers. The research on hybrid electrolytes has uncovered an important challenge: the organic-inorganic interface. In some cases, these interfaces can greatly decrease ionic conductivity and thus hinder battery performance. A better understanding of the chemical, physical and electrochemical properties (conductivity, stability) is crucial to master the development of competitive hybrid electrolytes. This PhD will focus on the understanding of the cohesion, stability, and ion transfer mechanisms at the polymer-inorganic electrolyte interface of hybrid electrolytes from an atomistic point of view by using a molecular simulation approach. First a realistic description of the interfaces at the atomistic scale will be performed with models based on preexisting first principles calculations. These results will be used for the development of accurate intermolecular potentials including polarizable effects. Then, explicit simulations of the solid inorganic electrolyte-polymer interfaces will be performed on simplified models to understand the effect of the interface structure on important properties (adhesion forces, ion transport, etc.). The aim will be to develop characterization and modeling techniques of the interface that can be extended to other families of hybrid electrolytes, or even the study of phases whose presence is not known (in a predictive mode).

Keywords: Energy conversion, hybrid materials, inorganic solid electrolytes, solid polymers, ionic transport, interfaces, molecular simulation, lithium-ion batteries.

• Academic & IFPEN supervisor    Dr Carlos NIETO-DRAGHI, IFPEN, ORCID : 0000-0001-5956-9259
• Doctoral School    ED388 Chimie Physique et Analytique de Paris Centre, Sorbonne Université 
• PhD location    IFPEN, Rueil-Malmaison, France   
• Duration and start date    3 years, starting in the fourth quarter 2024
• Employer    IFPEN
• Academic requirements    University Master degree in Chemistry, Physical Chemistry, Physics
• Language requirements    English level B2 (CEFR)
• Other requirements    General knowledge in physical-chemistry with notions in the following fields: electrochemistry, molecular modelling, programming (Python). Skills in composite materials chemistry or formulation would be a plus.

To apply, please send your cover letter and CV to the IFPEN supervisor indicated below.