Towards advanced electrolytes for sodium-ion batteries: in situ and in operando investigation of the negative electrode interface.

• Grant number: 24/20532-1
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: June 01, 2025
• End date: May 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Roberto Manuel Torresi
• Grantee: Vinícius Dias Silva
• Supervisor: Riccardo Ruffo
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Università degli Studi di Milano-Bicocca, Italy
• Associated to the scholarship: 22/12609-9 - Hard carbon nanofibers as a self-supporting negative electrode for the next generation of sodium-ion batteries, BP.PD

Abstract

This project aims to complement ongoing research exploring the use of self-supporting hard carbon nanofiber (HCNF) electrodes as negative electrodes in sodium-ion batteries (SIBs). Although these electrodes demonstrate high capacity in mAh g¿¹ and notable chemical and mechanical stability, it remains necessary to enhance the initial coulombic efficiency (ICE) to meet practical application requirements. To achieve these advancements, the project aims to develop hybrid electrolytes (HE) that integrate organic solvents and water, enhancing compatibility and synergy with electrode materials. Additionally, the project will also focus on quasi-solid electrolytes (QSE), which offer a balance of high ionic conductivity, safety, and structural stability. Solvents and materials selection will prioritize safety in terms of toxicity and flammability, as well as low-cost sodium salts with reduced environmental impact and technological relevance. For the first time, the research will leverage advanced techniques such as dynamic electrochemical impedance spectroscopy (EIS - in operando), Raman spectroscopy, and operando X-ray absorption spectroscopy (XAS) and small angle neutron and Xray scattering (SANS and SAXS) to analyze, in real time, the electrochemical behavior of interactions between the news electrolytes and HCNF electrodes. This approach will enable a detailed understanding of lesser-studied phenomena, enabling the development of more efficient and sustainable SIBs. Thus, this project aims to increase the energy efficiency of the SIBs under development in the current study (postdoc), and to provide safe and economically accessible alternatives in electrolytes for energy storage devices, moving towards more sustainable and viable solutions.