In situ electron microscopy of lithium electrodeposition behavior using electrochemical liquid flowing graphene chip

Abstract

Recently, liquid phase in situ transmission electron microscopy (TEM) has gained significant interest as a tool for battery research. Among the factors that affect the accuracy of in situ obtained data, membrane and electrode materials are crucial for electrochemical experiments. At the current state of electrochemical liquid chip development, a relatively thick SiNx membrane hinders the achievement of high-resolution imaging. In addition, electrode materials utilized in liquid chips are not standard for Li batteries and tend to form an alloy with Li. To enhance the quality and apply a full spectrum of TEM capabilities on the study of liquid samples, the further development of in situ platforms, including integration of new membrane materials and electrochemically stable electrodes in demand. This research includes the fabrication of electrochemical liquid flowing graphene chip (ec-LFGC) and its application for in situ TEM observation of Li electrodeposition behavior. Ec-LFGC is comprised of graphene membrane and Cu working electrode, which is a current collector in Li-based batteries. Transparency of graphene to an electron beam enables high-resolution imaging, and the inertness of the Cu electrode to the Li battery system eliminates possible side reactions. Therefore, ec-LFGC has tremendous potential for battery research and allows drawing a fundamental understanding of the common issues of batteries, such as Li dendrite growth mechanism and solid electrolyte interface evolution.