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Non‐aqueous lithium‐oxygen batteries (LOBs) have emerged as a promising candidate due to their high theoretical energy density and eco‐friendly cathode reaction materials. However, LOBs still suffer from high overpotential and poor cycling stability resulting from difficulties in the decomposition of discharge reaction Li2O2 products. Here, a 3D open network catalyst structure is proposed based on highly‐thin and porous multi‐metal oxide nanofibers (MMONFs) developed by a facile electrospinning approach coupled with a heat treatment process. The developed hierarchically interconnected 3D porous MMONFs catalyst structure with high specific surface area and porosity shows the enhanced electrochemical reaction kinetics associated with Li2O2 formation and decomposition on the cathode surface during the charge and discharge processes. The uniquely assembled cathode materials with MMONFs exhibit excellent electrochemical performance with energy efficiency of 82% at a current density of 50 mA g−1 and a long‐term cycling stability over 100 cycles at 200 mA g−1 with a cut‐off capacity of 500 mAh g−1. Moreover, the optimized cathode materials exhibit a remarkable energy density of 1013 Wh kg−1 at the 100th discharge and charge cycle, which is nearly four times higher than that of C/NMC721, which has the highest energy density among the cathode materials currently used in electric vehicles. [ABSTRACT FROM AUTHOR]

The article titled "Hierarchically Interconnected 3D Catalyst Structure of Porous Multi-Metal Oxide Nanofibers for High-Performance Li-O2 Batteries" discusses the development of a new catalyst structure for Li-O2 batteries. The researchers, Kim, Sohn, and their colleagues, have created a hierarchical architecture of thin and porous multi-metal oxide nanofibers with a 3D open network of interconnected catalysts. This structure increases the active surface area and provides rapid access channels, improving the electrochemical reaction kinetics and allowing for the reversible and effective formation and decomposition of Li2O2 in Li-O2 batteries. [Extracted from the article]

Advanced catalysts for clean hydrogen generation and storage offer an attractive possibility for developing a sustainable and ecofriendly future energy system. Transition metal oxides (TMO) are appealing candidates to be largely considered as electrode catalysts. However, for practical applications, there are still challenges—the intrinsic catalytic properties of TMOs should be further improved and TMOs should be synthesized by practical routes for cost-effective and scalable production of catalysts. Therefore, finding promising ways to fabricate highly active TMOs with outstanding electrochemical hydrogen evolution performance is required. Here, we present a direct and facile synthetic approach to successfully provide highly efficient MoO3−X catalysts with electrochemically active oxygen vacancies through a one-step thermal activation process on a Mo metal mesh. Variations in the oxidation states of molybdenum oxides can significantly increase the active sites of the catalysts and improve the electrochemical activity, making these oxide compounds suitable for hydrogen evolution reaction (HER). Compared to the bare Mo mesh and fully oxidized Mo (MoO3) electrodes, the fabricated MoO3−X electrode exhibits better electrochemical performance in terms of overpotentials and Tafel slope, as well as the electrochemical 1000 cycling stability, confirming the improved HER performance of MoO3−X. This provides new insight into the simple procedure suitable for the large-production supply. [ABSTRACT FROM AUTHOR]

Non-aqueous lithium-oxygen batteries (LOBs) have emerged as a promising candidate due to their high theoretical energy density and eco-friendly cathode reaction materials. However, LOBs still suffer from high overpotential and poor cycling stability resulting from difficulties in the decomposition of discharge reaction Li 2 O 2 products. Here, a 3D open network catalyst structure is proposed based on highly-thin and porous multi-metal oxide nanofibers (MMONFs) developed by a facile electrospinning approach coupled with a heat treatment process. The developed hierarchically interconnected 3D porous MMONFs catalyst structure with high specific surface area and porosity shows the enhanced electrochemical reaction kinetics associated with Li 2 O 2 formation and decomposition on the cathode surface during the charge and discharge processes. The uniquely assembled cathode materials with MMONFs exhibit excellent electrochemical performance with energy efficiency of 82% at a current density of 50 mA g -1 and a long-term cycling stability over 100 cycles at 200 mA g -1 with a cut-off capacity of 500 mAh g -1 . Moreover, the optimized cathode materials exhibit a remarkable energy density of 1013 Wh kg -1 at the 100th discharge and charge cycle, which is nearly four times higher than that of C/NMC721, which has the highest energy density among the cathode materials currently used in electric vehicles., (© 2024 Wiley‐VCH GmbH.)

The lattice oxygen mechanism (LOM) offers an efficient reaction pathway for oxygen evolution reactions (OERs) in energy storage and conversion systems. Owing to the involvement of active lattice oxygen enhancing electrochemical activity, addressing the structural and electrochemical stabilities of LOM materials is crucial. Herein, a heterostructure (Bi/BiCeO 1.8 H) containing abundant under-coordinated oxygen atoms having oxygen nonbonding states is synthesized by a simple electrochemical deposition method. Given the difference in reduction potentials between Bi and Ce, partially reduced Bi nanoparticles and surrounding under-coordinated oxygen atoms are generated in BiCeO 1.8 H. It is found that the lattice oxygen can be activated as a reactant of the OER when the valence state of Bi increases to Bi 5+ , leading to increased metal-oxygen covalency and that the oxophilic Ce 3+ / 4+ redox couple can maintain the Bi nanoparticles and surrounding under-coordinated oxygen atoms by preventing over-oxidation of Bi. The anion exchange membrane water electrolyzer with Bi/BiCeO 1.8 H exhibits a low cell voltage of 1.79 V even at a high practical current density of 1.0 A cm -2 . Furthermore, the cell performance remains significantly stable over 100 h with only a 2.2% increase in the initial cell voltage, demonstrating sustainable lattice oxygen redox., (© 2024 Wiley‐VCH GmbH.)