Ion Transport in Soft Matter Battery Electrolytes and Related Interphases

The development of next generation batteries depends heavily on the capability of electrolytes to quickly and selectively transport cations, and form stable electrochemical interfaces. In high energy density alkaline and alkaline earth metal anode batteries, issues such as dendrite and continuous solid electrolyte interphase (SEI) growth can be addressed by suitable interfacial and electrolyte chemistry.

 

In the first part of my talk, current understanding of ion transport mechanisms and related electrochemical measurement techniques (impedance spectroscopy, galvanostatic polarization) in soft matter battery electrolytes including liquids, polymers and hybrid (e.g. liquid/oxide and polymer/solid state electrolyte) materials will be discussed. According to this discussion, I will give guidelines and examples of improvements of the relevant electrochemical properties including ionic conductivity and the cationic transference number. 

 

In the second part of my talk, I will show recent findings related to the electrochemical and chemical growth and transport in SEIs on several alkali and alkaline earth metal anodes in contact with liquid electrolytes. The multitechnique approach showed that such SEIs are complex composite liquid/solid materials, with sometimes predominant ionic pathways in the liquid phase. The relevance of the native passive layer on alkali and alkaline earth metals, possibility of forming artificial SEIs (e.g. sulfides and Al2O3) and electrodeposition through porous SEI will be discussed. Finally, I will show a new modelling approach for treatment of impedance spectroscopy data of symmetric alkaline and alkaline earth metal cells.