/Electrochemistry of Lithium against ionic liquids; modelling the influence of “dielectric” solvents as additives

Electrochemistry of Lithium against ionic liquids; modelling the influence of “dielectric” solvents as additives

Leuven | More than two weeks ago

Working at the hart of the battery
Lithium-ion technology is ubiquitous in the contemporary society in varied applications. This is primarily because of their high volumetric and gravimetric energy density, which is unmatched by any other alkali metal ion. State-of-the art cells today reach nearly 700 Wh/L and further ambition for next generation batteries target 1000 Wh/L, which can be realised through Li metal anodes in conjunction with solid state electrolytes. At the heart of this futuristic technology is the process of continuous plating and stripping of Lithium during cycling of the battery. Owing to the highly reactive nature of Li, this is a complicated process shadowed with several complications during both plating (for e.g., dendrite formation and growth, dead lithium, continuous interface change, short circuit etc.) and stripping (void formation, pitting, broken interface layers etc.). Electrode architecture and the choice of electrolytes are some of the key factors that affect electrochemical performance of Li anode. 

 

Here at imec, we are evaluating various ionic liquid-based electrolytes (ILEs) for successfully mitigating the issues faced by Li anodes. Of importance here is the electrical double layer (EDL) that is formed at the vicinity of the reactive Li metal, which dictates the formation of the so-called solid electrolyte interphase (SEI). The nature and properties of the EDL and the SEI can be controlled by changing the composition of the ILEs (concentration of the salt, cosolvent) as well as by chemical/electrochemical preconditioning. In this project, the effect of various cosolvents and their concentration will be evaluated. Cosolvents change the coordinating structure around Li+ and hence the effective charge in its solvation environment in the electrolyte. This in turn affects structure of the interphase layer and Li0 plating (deposition) potential. During stripping (dissolution) cycle, Li+ ions move through this interphase layer and hence, the entire process of deposition/dissolution is changed by addition of cosolvents. 

 

The prospective student will examine the effect of variation cosolvent concentration in ILE’s and systematically study the resulting changes in physical and electrochemical properties of Li deposition/dissolution process. Such fundamental knowledge can be a starting point to successfully engineer superior functioning Li anodes.



Type of project: Thesis, Internship

Duration: 1 year

Required degree: Master of Engineering Science, Master of Science

Required background: Nanoscience & Nanotechnology

Supervising scientist(s): For further information or for application, please contact: Sai Gourang Patnaik (Sai.Gourang.Patnaik@imec.be)

Only for self-supporting students.