Showing papers by "Yongsheng Fu published in 2022"

Synergism of Flame‐Retardant, Self‐Healing, High‐Conductive and Polar to a Multi‐Functional Binder for Lithium–Sulfur Batteries

Abstract: In this work, a multifunctional binder with self‐healing, flame retardant, high conductivity, and abundant polar groups is prepared by the free radical polymerization method and applied to lithium–sulfur (Li‐S) batteries to achieve high safety and exceptional electrochemical performance. The self‐healing characteristic of binder induced by intermolecular hydrogen bonds and SS dynamic covalent bonds can repair volume expansion cracks. The polar groups and excellent conductivity endue binder with strong chemisorption on polysulfides and fast charge transportation, which can effectively inhibit the shuttle effect and accelerate polysulfides redox kinetics. More important, the considerable flame retardant performance of binder can improve the safety of the LiS batteries. As a result, the LiS cells using FHCP binder deliver an outstanding cycle stability of a high‐capacity retention rate of 85% after 100 cycles at 0.2 C, and a high reversible area specific capacity of 5.25 mAh cm–2 at a sulfur loading of 4.72 mg cm–2 and a correspondingly lean electrolyte condition (E/S ratio = 6 µL mg–1).

Synergistic Cation–Anion Regulation of Polysulfides by Zwitterionic Polymer Binder for Lithium–Sulfur Batteries

Abstract: The practical application of lithium–sulfur (Li–S) batteries is gravely hampered by the dissolution and shuttle of lithium polysulfides. Herein, a zwitterionic polymer binder with both lithiophilicity and sulfophilicity is skillfully designed to realize a synergistic regulation of cations and anions through the strong interactions with lithium polysulfides. The cationic quaternary ammonium group within the polymeric zwitterion can immobilize polysulfide anions and block polysulfide migration, while the sulfonate anions preferably couple with lithium ion, thus facilitating ion transfer and promoting the polysulfides redox kinetics. The dynamic networks crosslinked by both hydrogen bonding and electrostatic interaction enable mechanically robust cathodes to withstand the volume variation and spontaneously repair cracks upon repeated lithiation/delithiation. Benefiting from these attributes, the Li–S coin cell using the zwitterionic polymer binder delivers a high initial discharge capacity of 1230.6 mAh g−1 at 0.2 C as well as an ultralow capacity decay rate of 0.03% per cycle over 600 cycles at 2 C. In Li–S pouch cell level, a high areal capacity of 6.6 mAh cm−2 after 50 cycles can be obtained under a sulfur loading of up to 8.5 mg cm−2, demonstrating the potential of zwitterionic polymer binder for the further development of high‐performance Li–S batteries.

Boosting Alkaline Hydrogen Evolution on Stoichiometric Molybdenum Carbonitride via an Interstitial Vacancy‐Elimination Strategy

Abstract: An interstitial vacancy on molybdenum nitride has been determined as a negative factor towards the alkaline hydrogen evolution reaction (HER) by reason of upraising the d orbitals of Mo. Nevertheless, investigations aiming to eliminate the vacancies are rarely reported. Here, an interstitial reconfiguration method for the design of stoichiometric molybdenum carbonitride (Mo2CN) is proposed, in which the vacancies are fulfilled by lattice carbon. Multiple fine structural analyses alongside with the theoretical calculations indicate that beyond lower the d orbitals of Mo by the hybridization of additive p‐d orbitals, lattice carbon also behaves as the extra active center with exceptional H adsorption/desorption energy. Mo2CN reveals an adorable overpotential of −84 mV at a current density of 10 mA cm−2 with a long‐term electrochemical stability by accompanying the nitrogen‐doped carbon substrate. It is anticipated that the vacancy‐eliminating concept will provide a constructive entry point for the rational design of electro‐catalysts and beyond.

Nanostructure and phase engineering integration of amorphous Ni-Co sulfide/crystalline MnS/rGO cathode and ultra-small Fe2O3 nanodots/rGO anode for all-solid-state asymmetric supercapacitors

Abstract: Engineering high-performance electrode materials is crucial to boost specific capacitance/energy of supercapacitors but challenging. Herein, amorphous Ni-Co sulfide/crystalline MnS and ultra-small Fe2O3 nanodots are skillfully integrated on reduced graphene oxide sheets to construct a-Ni-Co-S/c-MnS/rGO and Fe2O3 NDs/rGO, respectively. The integrated hybrid architectured a-Ni-Co-S/c-MnS/rGO cathode exhibits a high specific capacity of 1248 C g−1 at 2 A g−1 and long-term cyclic stability, induced by unique amorphous/crystalline heterophase nanostructure and electrical conductivity of rGO. Meanwhile, the resultant Fe2O3 NDs/rGO anode shows an impressive specific capacity of 734.2 C g−1 at 2 A g−1 with excellent rate capability (77.9%), which can be ascribed to unimpeded electron/ion diffusion pathways and abundant active sites endued by the nanodots-on-nanosheets structure of Fe2O3 NDs/rGO. Benefiting from the phase and nanostructure engineering integration, the all-solid-state asymmetric supercapacitor based on a-Ni-Co-S/c-MnS/rGO and Fe2O3 NDs/rGO shows a high specific energy of 42.0 Wh kg−1 at 793.8 W kg−1 and outstanding capacity retention (83.6% after 10,000 cycles).

Progress of NiO‐Based Anodes for High‐Performance Li‐Ion Batteries

Abstract: Rechargeable lithium‐ion batteries (LIBs) are of great significance to the development of renewable energy. The traditional graphite anode is gradually unable to meet increasing demands for high energy density and power density due to its low theoretical capacity. NiO has gained considerable attention because of its high theoretical capacity, low toxicity, and stable chemical properties. This review summarizes the research progress of NiO‐based nanomaterials in LIBs and centers on the electrochemical reaction mechanism, synthesis methods, and strategies for improving the electrochemical properties of NiO anodes. The results demonstrate that the electrochemical characteristics highly depend on the synthesis method, morphology, surface area, conductive substrate, etc. Compared with pure NiO, NiO‐based composites including NiO/carbon‐based materials and NiO/metal oxide often present higher capacity and cycle stability. Furthermore, challenges and future perspectives of NiO‐based anodes are also discussed.

Vanadium disulfide-coated carbon nanotube film as an interlayer for high-performance lithium‑sulfur batteries

Abstract: Owing to the “shuttle effect” and slow solid–solid reaction of Li2S2–Li2S, the capacity of lithium‑sulfur batteries cannot be fully actualized, and the capacity loss is rapid. To address this issue, in this study, a vanadium disulfide-coated carbon nanotube film (VS2@CNTF), fabricated using floating catalyst chemical vapor deposition following a hydrothermal reaction, was adopted as the interlayer in the sulfur cathode. The initial discharge capacity of the Li-S battery with the VS2@CNTF interlayer was 1432.9 mA·h·g−1 at 0.2 C, which was 85.6% of the theoretical capacity of sulfur. Even at a sulfur loading of 3.6 mg cm−2, the Li-S battery with a VS2@CNTF interlayer demonstrated a discharge capacity of 970.6 mA·h·g−1 after 200 cycles at 1 C. This outstanding performance of the sulfur cathode is partially attributed to the three-dimensional electrical conductive networks formed by the ultra-long intertwined carbon nanotubes, which facilitate the effective adsorption of lithium polysulfides by the VS2@CNTF interlayer, inhibiting the “shuttle effect.” Furthermore, VS2@CNTF catalyzed the solid–solid reaction of Li2S2–Li2S to accelerate the reaction kinetics, thereby enhancing the rate performance.

Supramolecular assembly-derived carbon-nitrogen-based functional materials for photo/electrochemical applications: Progress and challenges

Abstract: : Supramolecular chemistry during the synthesis of carbon-nitrogen-based materials has recently experienced a renaissance in the arena of photocatalysis and electrocatalysis. In this review, we start with the discussion of supramolecular assemblies-derived carbon-nitrogen-based materials’ regulation from the aspect of morphology, chemical composition, and micro/nanostructural control. Afterwards the recent advances of these materials in energy and environment related applications, including degradation of pollutants, water splitting, oxygen reduction reactions, CO 2 reduction reactions along with organic synthesis are summarized. The correlations between the structural features and physicochemical properties of the carbon-nitrogen-based materials and the specific catalytic activity are discussed in depth. By highlighting the opportunities and challenges of supramolecular assembly strategies, we attempt an outlook on possible future developments for highly efficient carbon-based photo/electrocatalysts.