Impact of ethyl tris-2-methoxyethoxy silane on the passivation of graphite electrode in Li-ion cells with PC-based electrolyte

The aim of this work was to study the influence of ethyl tris-2-methoxyethoxy silane (compound belonging to the class of silanes referred to as silicon tripodands) on the formation of passive layer (often called solid electrolyte interphase) on the electrode made of highly graphitic material during first reduction in propylene carbonate-based (PC) electrolytes. The podand molecules were introduced to the system as additives (co-solvents) to PC and as surface pre-treatment agents for graphite electrodes. It was found that in the presence of podand graphite anode functions properly in PC-containing electrolytes and no detrimental solvent co-intercalation is observed. These phenomena have been ascribed to partial hydrolysis of podand molecules on the graphite surfaces, leading to the formation of a two-dimensional polymeric network via Si–O–Si bonds. Electrochemical characterization involved galvanostatic charging/discharging and cycling voltammetry experiments. On the basis of the presented findings new industrially viable, low-cost, low-temperature Li-ion cell designs can be developed.