Xuhuan Yang

Bio: Xuhuan Yang is an academic researcher from South China Agricultural University. The author has contributed to research in topics: Oxygen evolution & Monolith. The author has an hindex of 1, co-authored 2 publications receiving 15 citations.

An amorphous trimetallic (Ni–Co–Fe) hydroxide-sheathed 3D bifunctional electrode for superior oxygen evolution and high-performance cable-type flexible zinc–air batteries

Abstract: The emerging flexible/wearable electronics have greatly stimulated research on portable batteries with high specific energy and excellent mechanical properties. State-of-the-art zinc–air batteries (ZABs) are potential candidates for flexible energy supply; however, their development is hindered by the sluggish kinetics of the oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) of an air cathode. Herein, we demonstrate a 3D integrated bifunctional oxygen electrode of NiCo2O4@NiCoFe–hydroxide nanoarrays for flexible all-solid-state ZABs. Owing to the intact mesoporous nanoarrays synergized with the amorphous trimetallic hydroxide sheath, the free-standing NiCo2O4@NiCoFe–hydroxide electrode exhibited excellent bifunctional activities with an ultralow potential difference of 695 mV between OER and ORR. The NiCo2O4@NiCoFe–hydroxide-based planar aqueous ZAB achieved high discharge capacity (723 mA h gzinc−1 at 10 mA cm−2), high energy density (864.2 W h kgzinc−1 at 5 mA cm−2) and long cycle life of up to 250 h. More significantly, cable-type all-solid-state ZABs fabricated with the 3D oxygen electrode demonstrated an impressive volumetric energy density of 38.1 mW h cm−3 and high mechanical flexibility even after 2000 bending cycles, highlighting their enormous potential for flexible/wearable energy applications.

Interface reinforced 2D/2D heterostructure of Cu-Co oxides/FeCo hydroxides as monolithic multifunctional catalysts for rechargeable/flexible zinc-air batteries and self-powered water splitting

Abstract: Elaborate engineering of heterostructure and composition to regulate the electroactivities remains a pronounced challenge. Herein, a self-supported 2D/2D heterostructure monolith is constructed by interlinked FeCo-hydroxides nanosheets tightly interlacing with aligned Cu0.76Co2.24O4 nanoplates. Due to the well-defined hierarchical nanoarrays and desirable interfacial coupling, the monolithic catalyst can guarantee the rapid charge transfer and mass transport pathways for accelerated surface kinetics, leading to manifestly improved electroactivities and stability toward trifunctional catalysis. Both experimental and theoretical calculations unravel the enriched multimetal active sites for intermediates adsorption and the synergistic interplay of the heterostructure to achieve enhanced catalytic efficiency. Consequently, the heterostructure catalyst contributes to high-performance rechargeable/flexible all-solid-stated Zn-air batteries and water electrolyzer with an ultralow potential of 1.51 V. Moreover, self-powered water splitting system driven by flexible Zn-air batteries delivers a high H2 generation rate. This cost-effective heterostructure monolith could open an intriguing avenue for advancing all-in-one films toward portable energy conversion/storage.

Hierarchical trimetallic Co-Ni-Fe oxides derived from core-shell structured metal-organic frameworks for highly efficient oxygen evolution reaction

Abstract: Metal-organic frameworks (MOFs) have recently emerged as promising precursors to construct efficient non-noble metal electrocatalyst for oxygen evolution reaction (OER) Herein, a Co-Ni-Fe spinel oxide-carbonitrides hybrids (CoNiFeOx-NC) electrocatalyst with hierarchical structure was synthesized from Fe-MIL-101-NH2 through a unique ion-exchange based strategy The ion exchange of Fe-MIL-101-NH2 with both Ni and Co ions induced a hierarchically structured 2-D ternary metal MOF shell layer encapsulated 3-D octahedral MOF crystals as a core This prevents the collapse of MOF frameworks during the air calcination process and affords highly porous structure and large surface area Additionally, the unique combination of Co-Ni-Fe in spinel oxides derived from calcination of the hierarchically structured core-shell MOF provides a favorable electronic environment for the adsorption of OER intermediates, which was further verified by the XPS characterizations and DFT calculations DFT study revealed the Ni-Co coordinated Oh sites in the MFe2O4 reverse spinel structures as the main active sites, which tuned the binding strength of oxygen species with a catalyst through electron transfer of Fe→Co→Ni, thereby lowered the energy barriers for OER As a result, the rationally designed CoNiFeOx-NC catalyst manifests superior OER performance with a low overpotential of 265 mV at 50 mA cm−2 and a decent Tafel slope of 641 mV dec-1 The ion-exchange based strategy may serve as a versatile platform for rational design and synthesis of multi-metallic MOF derived electrocatalysts

First-row transition metal-based materials derived from bimetallic metal-organic frameworks as highly efficient electrocatalysts for electrochemical water splitting

Abstract: Electrochemical water splitting is a mature technology for hydrogen generation. Numerous studies have focused on the development of highly efficiency electrocatalysts to produce hydrogen and oxygen from water electrolysis through...

Binder-Free Air Electrodes for Rechargeable Zinc-Air Batteries: Recent Progress and Future Perspectives

Abstract: Designing an efficient air electrode is of great significance for the performance of rechargeable zinc (Zn)-air batteries. However, the most widely used approach to fabricate an air electrode involves polymeric binders, which may increase the interface resistance and block electrocatalytic active sites, thus deteriorating the performance of the battery. Therefore, binder-free air electrodes have attracted more and more research interests in recent years. This article provides a comprehensive overview of the latest advancements in designing and fabricating binder-free air electrodes for electrically rechargeable Zn-air batteries. Beginning with the fundamentals of Zn-air batteries and recently reported bifunctional active catalysts, self-supported air electrodes for liquid-state and flexible solid-state Zn-air batteries are then discussed in detail. Finally, the conclusion and the challenges faced for binder-free air electrodes in Zn-air batteries are also highlighted.