Engineering Materials, Electrolytes and Interphases in Sodium Ion Batteries: Challenges, Design Rules, and Pathways to Practical Systems (09/04/26)
Speaker and Affliation:
Dr. Sathiya Mariyappan
Research Scientist at CNRS, France
When?
9th April, 2026 (Thursday), 3.00 PM (India Standard Time)
Where
KPA Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
Functional materials in batteries, particularly electrodes and electrolytes, often operate far from thermodynamic equilibrium, relying on kinetic stabilization via interphase formation. The electrode–electrolyte interphase (EEI), typically only a few nanometers thick, plays a decisive role in governing ion transport, interfacial stability, and degradation across battery chemistries, making its rational control critical for enhanced performance. These challenges are further exacerbated in emerging chemistries such as sodium-ion batteries, owing to the higher solubility of Na-based interphases compared with their lithium counterparts.
Accordingly, the first part of my talk will adopt a materials-centric perspective, focusing on the challenges we encountered in tuning interfacial chemistry through electrode structure–property relationships and electrolyte engineering. I will illustrate this approach using Na₃V₂(PO₄)₂F₃/Hard carbon (HC) and layered oxide/HC based sodium-ion cells, which are representative of industrially relevant sodium-ion technologies at present.2,3 In particular, I will demonstrate how interphase stability can be tailored through insights gained from advanced operando temperature–pressure sensing, combined with in situ and ex situ IR, NMR, and microscopic analyses. Looking ahead, increasing the volumetric energy density of sodium-ion cells necessitates a transition from hard carbon to alloying anodes such as tin. This shift introduces multifaceted challenges arising from continuous volume changes during sodiation and desodiation, as well as pronounced interphase instability.4 These challenges will be discussed with cautious optimism, inspired by the recent advances in silane-based interfacial strategy5 that have enabled the successful deployment of silicon alloying anodes in lithium-ion batteries.
Finally, I will conclude by outlining a vision for building a long-term research program through close collaboration with chemists, spectroscopists, and metallurgists, aimed at materials-driven interface engineering for next-generation energy storage technologies.
Short Bio of Speaker:
Sathiya Mariyappan is an Indian materials researcher with a strong background in electrochemistry, currently working as a Chargée de recherche at CNRS, France, since 2018- a position roughly equivalent to CSIR scientists in India. She leads and coordinates the sodium-ion research theme at the CSE laboratory (UMR 8260), Collège de France, headed by Prof. Jean-Marie Tarascon, one of the pioneers of lithium-ion batteries.
Prior to joining CNRS, she carried out postdoctoral research at LRCS, Amiens, France, where, together with her collaborators, she helped establish the concept of anionic redox in battery materials, challenging the long-standing focus on cationic redox processes. This work opened new directions in materials research while also revealing key limitations that continue to drive current efforts toward the practical implementation of anionic-redox-based materials. At CSE, building on approximately 15 years of research experience in lithium- and sodium-ion battery materials, interphase analysis, and electrolyte optimization, her research bridges fundamental materials science and applied electrochemistry. Her work has resulted in patented technologies transferred for commercialization in sodium-ion batteries. She is a member of the French energy storage research network (RS2E) and is actively involved in national (PEPR-ANR) and European (NAIMA) battery research programs, while maintaining a strong interest in collaborative and interdisciplinary research. In addition to supervising PhD students and postdoctoral researchers, she teaches Materials for Energy Devices to master’s students at PSL and regularly delivers invited talks at major international conferences.