Facilitating Oxygen Redox on Manganese Oxide Nanosheets by Tuning Active Species and Oxygen Defects for Zinc‐Air Batteries

Abstract

Bifunctional oxygen catalyst is an important component in the cathode for rechargeable zinc‐air batteries. MnO2 catalysts have aroused intense interests owing to their promising activity for oxygen reduction reaction (ORR), which, however, is still not comparable to precious metal catalysts. To improve the ORR catalysis and meet the requirement for a bifunctional oxygen catalyst, MnO2 nanosheets are modified with Co, Ni or Fe via a facile solution‐based method. Among the modified samples, Co−MnO2 presents improved catalysis for both ORR and oxygen evolution reaction (OER). The modification introduces additional active sites for OER and induced more oxygen defects to further facilitate the ORR. Zn‐air batteries with the Co−MnO2 air cathode showed a higher peak power density of 167 mW cm−2, a lower potential gap of 0.75 V and a higher round‐trip efficiency of 63 % (5 mA cm−2) compared to MnO2 without modification. Good cycling stability of the battery is also achieved. The proper amount of cobalt species in the MnO2 is vital for achieving a balance between high performance and durable cycling.

A new material discovery platform of stable layered oxide cathodes for K-ion batteries

“…Recently, K-ion batteries (KIBs) have shown great potential to become a competing technology to the LIBs for large-scale energy storage systems in the future. [58][59][60][61][62] In this work, for the first time, we proposed a new material discovery platform assisted by a combination of ML model-prediction, DFT calculations, and experimental validation for KIBs. First, the ML model was built based on 27578 entries and then used to predict crystal stabilities of seven different proposed metal-doped K x MnO 2 samples before feeding into the DFT calculations for enhancing the physicochemical properties and environmental stability of the K x MnO 2 cathode.…”

Avoiding CO2 Improves Thermal Stability at the Interface of Li7La3Zr2O12 Electrolyte with Layered Oxide Cathodes

“…O K pre-edge intensity decreased as the number of oxygen vacancies increased in both studies. [50,51] Pre-edge intensity for the sample annealed in humidified O 2 was highest at 500 °C. Data from the sample annealed at 500 °C stood out since pre-edge intensity for the other temperature conditions in humidified O 2 decreased as annealing temperature increased.…”

Co3O4–NiCo2O4 Hybrid Nanoparticles Anchored on N-Doped Reduced Graphene Oxide Nanosheets as an Efficient Catalyst for Zn–Air Batteries

“…At the same time, the ORR kinetic mechanism is reflected by the electron transfer number (n). 43 The OER performance of the as-synthesized specimens was further examined (Figure 6a). In general, the index used to determine the OER property is the potential at 10 mA cm with splendid overpotential and Tafel slope exhibits pre-eminent OER kinetics.…”