Structure, dynamics, transport and electrochemical investigation of energy materials

Project description

Our project aims to develop cost-effective electrode materials with high energy density, cycling stability, and excellent rate capability. Among the various categories of cathode material, we have chosen V-based NASICONs i.e., Na3VM(PO4)3 (M= Ti, Fe, Zr, Mn, Al) as they show multielectron transfer reactions resulting in high capacity. Additionally, they have tunable operating voltage, good structural stability, and high ionic conductivity. The project begins with the synthesis of cathode materials by both top-down and bottom-up approaches, i.e., solid-state, and sol-gel methods which will be followed by their structural and electrochemical characterizations. To further stabilize the material, modification of the active material with carbon composites (nitrogen and sulfur-doped carbon, CNT, rGO) can be carried out because they can provide 3D connectivity networks by enhancing the diffusion coefficient of sodium and electronic conductivity. The stable (PO4)3- can reduce the volume expansion during Na insertion/extraction when compared with layered oxides. These properties of the phosphates make them interesting as cathodes in Na ion batteries for high electrochemical performances. The project will proceed to replace phosphate with fluorine and oxygen fluoride groups. The large electronegativity of fluorine ions in fluorophosphate causes high voltage and excellent energy densities with good cycling stability.

Outcomes

1) Synthesis of doped Na3V2-xMx(PO4)3 (M= Ti, Fe, Zr, Mn, Al) NASICON active cathode material.
2) Characterization of the active materials to study the physical and chemical properties.
3) Optimization of the carbon coating to improve electronic conductivity.
4) Fabrication of the coin cells for sodium-ion batteries.
5) Electrochemical characterizations to test the cells for their capacity and rate capability.
6) Thesis submission and high-impact publications.

Essential capabilities

Condensed Matter Physics and energy materials

Desireable capabilities

Materials fabricaiton and engineering

Expected qualifications (Course/Degrees etc.)

M.Sc. or M.Tech.

Additional information for applicants

note: i-students must have own scholarship to apply (CSIR, UCG-NET, etc)