Engineering Amorphous/Crystalline Structure of Manganese Oxide for Superior Oxygen Catalytic Performance in Rechargeable Zinc–Air Batteries

Abstract

Although amorphous materials are popular in oxygen electrocatalysis, their performance requires further improvement to meet the need for rechargeable zinc–air batteries. In this work, an amorphous/crystalline layered manganese oxide (ACMO) was designed, and its unique amorphous/crystalline homogeneous structure activated its oxygen reduction activity with a positive half‐wave potential of 0.81 V and oxygen evolution activity with a moderate overpotential of 407 mV at 10 mA cm−2. Moreover, the amorphous/crystalline structure endowed ACMO with excellent stability. While employed as the air‐electrode material for rechargeable zinc–air batteries, ACMO overcame the poor cycling stability of manganese oxide and cycled stably for 1000 cycles (≈17 days) at 10 mA cm−2. Besides, it delivered a high power density of 159.7 mW cm−2 and a narrow voltage gap of 0.66 V. This work gives an insight into designing oxide materials with amorphous/crystalline structure and feasible guidance for harmonizing electrochemical activity and stability.

Sunlight-driven and gram-scale vanillin production via Mn-defected γ-MnO2 catalyst in aqueous environment

“…The average oxidation states (AOS) of Mn species are calculated using the following formula. 28,29 AOS = 8.956 − 1.126DE s As shown in Fig. 2a, the calculated AOS values are 3.2, 3.4, and 3.9 for g-MnO 2 , g-MnO 2 (1), and g-MnO 2 (10), respectively, consistent with the Mn 3+ /Mn 4+ ratios (Fig.…”

“…The average oxidation states (AOS) of Mn species are calculated using the following formula. 28,29 AOS = 8.956 − 1.126Δ E s …”

Strong Electronic Interaction between Amorphous MnO2 Nanosheets and Ultrafine Pd Nanoparticles toward Enhanced Oxygen Reduction and Ethylene Glycol Oxidation Reactions

“…As shown in Mn 3s spectra (Figure 3b), the peak energies separation of Mn 3s (Δ E 3s ) for Pd/a‐MnO 2 , Pd/c‐MnO 2 , a‐MnO 2 , and c‐MnO 2 are 4.91, 4.83, 4.78, and 4.52 eV, respectively, suggesting the Mn average oxidation state (AOS) is 3.4, 3.5, 3.6, and 3.9. The AOS was calculated by the following equation: [ 20 ] $$\[ \begin{array}{*{20}{c}}{{\rm{AOS}} = 8.956 - 1.126\Delta {E_{3{\rm{s}}}}}\end{array} \]$$…”

Aptamer-mediated hollow MnO 2 for targeting the delivery of sorafenib

“…The 2p orbital electron binding energy of manganese atoms in nanoparticles was selected to be analyzed. The electron binding energy of Mn 2p 3/2 is 643.39, 642.12, and 640.48 eV respectively, indexing to Mn 4+ , Mn 3+ , and Mn 2+ species (Zhou et al., 2022 ). The nitrogen adsorption–desorption isotherm of H-MnO 2 was collected, and the corresponding specific surface area was calculated to be 58 m 2 g −1 ( Figure 4(C) ).…”