Altering Solvation at the Electrolyte/Electrode Interface in a Precisely Defined Manner

Calcium is a promising candidate in multivalent battery technologies because of its safe, economical, and nontoxic nature. It offers the promise of a more than two-fold increase in the volumetric capacity compared to monovalent lithium-ion batteries. The understanding of the solvation and charge transfer mechanism at the electrolyte/electrode interface and how different types of cations and anions will affect the calcium solvation at this interface is the key to developing novel calcium batteries since the solvation of an electrolyte near the interphase dictates the charge transfer efficiency and therefore affects the performance of a battery. However, current understanding regarding this interphase was limited due to the lack of direct interphase probing approaches under in-situ/operando conditions. In this talk, using synchrotron-based X-ray absorption spectroscopy and resonant soft X-ray scattering through a patterned e-chip, the solvation of a calcium organic electrolyte was investigated under operando conditions. The disruption of the solvation structure by a secondary anion or cation was evaluated using the methodologies developed, which will guide the designing of electrolytes for future energy storage. The strategy of these new methodologies developed will also benefit the investigation of catalysis at interphases and electrochemical microenvironments in general.