In operando observation of chemical and mechanical stability of Li and Na dendrites under quasi-zero electrochemical field

Abstract

Quasi-zero electrochemical fields generally refer to the electrochemical systems when external electrochemical process is halted, e.g. completion of charge/discharge, interruption of battery operation and massive battery decay under abuse. For understanding the chemical and mechanical features of lithium and sodium dendrites under quasi-zero electrochemical fields, in operando optical observation on the chemical and mechanical stability of metal dendrites is carried out in both symmetric lithium and sodium metal batteries. Without applied electrochemical field, sodium dendrite dissolution has been in situ observed upon settling the as-grown dendrites into the electrolytes. By applying fluid shear force and vibration force, mechanical stability studies suggest that the as-plated sodium dendrites are more vulnerable and sensitive to the external applied forces within the electrolyte. Coupled with the fundamental atomic and physical properties, the intrinsic feature and dissimilarity of the lithium and sodium dendrites are discussed, which offers remarkable insight into understanding the principles for using metal anodes under various conditions.