Reveal the Electrical Double Layer (EDL) in Zinc Battery Electrolytes with Electrocapillarity

The electrified interface between electrodes and electrolytes, aka, electrical double layer (EDL), resides at the heart of electrochemistry and exists universally in all electrochemical devices. It governs the kinetics and reversibility of all electrochemical processes, and predicts the interphase chemistries in advanced batteries. However, despite such importance, its understanding remains insufficient. While many theoretical models have been developed to predict EDL structure and to correlate key properties to the structures, so far there have been very rare direct experimental characterization, due to the limitations of existing techniques and the extreme elusiveness and sensitivity of the electrified interfaces. In this talk, I will discuss a modernized high-resolution electrocapillarity method, developed in my group. Applying this reborn electrocapillarity on a bivalent electrolyte of ZnCl2 and ZnSO4, we reveal the interfacial structure of Zn ion battery electrolytes in the absence and presence of anion specific adsorption and established the abnormal potential distribution across the interface due to anion adsorption and its effect on the kinetics of Zn ion deposition chemistry.