Simeng Li

Bio: Simeng Li is an academic researcher from South China Agricultural University. The author has contributed to research in topics: Oxygen evolution & Hydroxide. The author has an hindex of 2, co-authored 4 publications receiving 51 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.

Simultaneous Encapsulation of Nano-Si in Redox Assembled rGO Film as Binder-Free Anode for Flexible/Bendable Lithium-Ion Batteries.

Abstract: The emerging ubiquitous flexible/wearable electronics are in high demand for compatible flexible/high-energy rechargeable batteries, which set a collaborative goal to promote the electrochemical performance and the mechanical strength of the fundamental flexible electrodes involved. Herein, freestanding flexible electrode of Si/graphene films is proposed, which is fabricated through a scalable, zinc-driven redox layer-by-layer assembly process. In the hybrid films, silicon nanoparticles are intimately encapsulated and confined in multilayered reduced graphene oxide (rGO) nanosheet films. The designed monolithic rGO/Si film possesses several structural benefits such as high mechanical integrity and three-dimensional conductive framework for accessible charge transport and Li+ diffusion upon cycling. When adopted as binder-free electrode in half-cells, the optimized hybrid rGO/Si film delivers high gravimetric capacity (981 mA h g-1 at 200 mA g-1 with respect to the total weight of the electrode) and exceptional cycling stability (0.057% decay per cycle over 1000 cycles at 1000 mA g-1). Besides, the binder-free rGO/Si film anode is further combined with a commercial LiCoO2 foil cathode for completely flexible full cell/battery, which exhibits excellent cycling performance and a high capacity retention of over 95% after 30 cycles under continuous bending. This solution-processable, elaborately engineered, and robust Si/graphene films will further harness the potential of silicon-carbon composites for advanced flexible/wearable energy storage.

Nickel cobalt iron hydroxide coated nickel cobaltate flexible electrode material and preparation and application thereof

Abstract: The invention belongs to the field of zinc-air battery air electrode materials, and discloses a nickel cobalt iron hydroxide coated nickel cobaltate flexible electrode material and preparation and application thereof. The preparation method comprises the following steps: performing in-situ solvothermal growth and air calcination on a conductive substrate to obtain a nickel cobaltate nano array, and performing solvothermal deposition on nickel cobalt iron hydroxide on the surface of the nickel cobaltate nano array by using soluble salts of three transition metals including nickel, cobalt and iron to obtain the nickel cobaltate flexible electrode material coated with the nickel cobalt iron hydroxide. According to the nickel cobalt iron hydroxide coated nickel cobaltate flexible electrode material disclosed by the invention, ion transmission and electrolyte diffusion are promoted by utilizing a three-dimensional porous network structure; the nickel cobaltate nanowire and the nickel-cobalt-iron hydroxide shell layer are combined to increase the number of active specific surfaces and active sites, so that the composite electrode material has excellent oxygen evolution reaction and oxygen reduction reaction performance, and high specific discharge capacity, high energy density and outstanding cycling stability are realized when the composite electrode material is applied to a rechargeable zinc-air battery.

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

Green Synthesis of Dual Carbon Conductive Network-Encapsulated Hollow SiOx Spheres for Superior Lithium-Ion Batteries

Abstract: Designing hollow/porous structure is regarded as an effective approach to address the dramatic volumetric variation issue for Si-based anode materials in Li-ion batteries (LIBs). Pioneer studies ma...