Decoupling the roles of carbon and metal oxides on the electrocatalytic reduction of oxygen on LaSrCoO perovskite composite electrodes.

Perovskite oxides are active room-temperature bifunctional oxygen electrocatalysts in alkaline media, capable of performing the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with lower combined overpotentials relative to their precious metal counterparts. However, their semiconducting nature necessitates the use of activated carbons as conductive supports to generate applicably relevant current densities. In efforts to advance the performance and theory of oxide electrocatalysts, the chemical and physical properties of the oxide material often take precedence over contributions from the conductive additive.

Anion-Based Pseudocapacitance of the Perovskite Library LaSr BO (B = Fe, Mn, Co).

We have synthesized a library of perovskite oxides with the composition LaSr BO ( x = 0-1; B = Fe, Mn, Co) to systematically study anion-based pseudocapacitance. The electrochemical capacitance of these materials was evaluated by cyclic voltammetry and galvanostatic charging/discharging in 1 M KOH. We find that greater oxygen vacancy content (δ) upon systematic incorporation of Sr linearly increases the surface-normalized capacity with a slope controlled by the B-site element.

Effects of Solute-Solvent Hydrogen Bonding on Nonaqueous Electrolyte Structure.

We investigate the source of Raman background signal commonly misidentified as fluorescence in nonaqueous electrolytes via a variety of spectroscopies (Raman, fluorescence, NMR) and find evidence of hydrogen-bonding interactions. This hydrogen bonding gives rise to broadband anharmonic vibrational modes and suggests that anions play an important and underappreciated role in the structure of nonaqueous electrolytes. Controlling electrolyte structure has important applications in advancing in operando spectroscopy measurements as well as understanding the stability of high concentration electrolytes for next-generation electrochemical energy storage devices.