Synergistic Catalysis of the Lattice Oxygen and Transition Metal Facilitating ORR and OER in Perovskite Catalysts for Li–O₂ Batteries

Abstract

The role of catalysts in aprotic Li−O 2 batteries remains unclear. To identify the exact catalytic nature of oxide catalysts, a precisely surface-engineered model catalyst, perovskite (LaMnO 3 ), was investigated for oxygen reduction reaction/ oxygen evolution reaction (ORR/OER) in both aqueous and aprotic solutions. By using integrated theoretical and experimental approaches, we explicitly show that H + -ORR/OER catalytic activity on transition-metal sites fails to completely describe the electrochemical performance of LaMnO 3 catalysts in aprotic Li−O 2 batteries, whereas the collective redox of the lattice oxygen and transition metal on the catalyst surface during initial Li 2 O 2 formation determines their discharge capacity and charge overpotential. This work applies oxide catalyst design to tailor both the surface lattice oxygen and the transition-metal arrangement for an aprotic Li−O 2 battery. The optimized model catalyst shows good performance for Li−O 2 batteries under both oxygen and ambient air (real air) conditions.

The Crucial Role of Water in the Stability and Electrocatalytic Activity of Pt Electrodes

“…Few mechanistic studies of oxygen and hydrogen conversion reactions have been performed in nonaqueous electrolytes. For example, the oxygen reduction reaction (ORR) has been studied in different organic electrolytes to identify appropriately active electrode materials and electrolyte composition for metal–air batteries. − Other studies investigated hydrogen oxidation/evolution to elucidate general reaction mechanisms. − One key question in those studies is the role of water at the electrode materialelectrolyte interface as a reactant, decoupled from its function as a solvent in aqueous media. ,− The concept of controlled addition of water to nonaqueous electrolytes can provide essential insights into mechanistic concepts. Pemberton et al proposed almost 30 years ago that water molecules cluster around supporting electrolyte ions and can be transported dependent on the potential to the electrode interface in butanol-based electrolytes.…”

Tailoring the d‐Band Centers of Perovskite Oxides for Electrochemical Ozone Production

“…Over the past few decades, ABO 3 -type perovskite oxides have emerged as important family of functional materials with diversified functions, [15,16] such as highly adjustable compositions, corrosion resistance, and flexible structures. [17,18] The lanthanum-element perovskite oxides, which are formed with the active transition metal with electronic structure degrees of freedom and flexible crystal structure, [19] can be well customized for electrochemical reactions, [20][21][22][23] and their role as oxygen electrocatalysts has gained renewed attention due to their favorable electrocatalytic activity toward oxygen reduction reactions (ORR) [24][25][26][27] and oxygen evolution reactions (OER). [28][29][30][31][32] Most lanthanum elements have a valence electron structure of 4f5d in the ground state, and A-site cations are generally believed to influence the electrocatalytic performance indirectly by adjusting the electronic structure of B-site ions in the perovskite lattice.…”

Cation‐Exchange‐Induced Metal and Alloy Dual‐Exsolution in Perovskite Ferrite Oxides Boosting the Performance of Li‐O2 Battery

“…Perovskite oxides such as LaFeO 3 , [1] LaMnO 3 , [2] and La 0.75 Sr 0.25 MnO 3 [3] have attracted much recent attention as the catalyst support in Li‐O 2 batteries because of their tuneable physical and chemical properties. However, the high overpotential and poor stability of the perovskite oxides suffer from the oxidizing environment of the Li‐O 2 battery during charge and discharge remain challenging.…”