Jiafeng Zhou

Bio: Jiafeng Zhou is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Anode & Catalysis. The author has an hindex of 10, co-authored 15 publications receiving 286 citations. Previous affiliations of Jiafeng Zhou include University of Science and Technology of China.

Glucose-Induced Synthesis of 1T-MoS2/C Hybrid for High-Rate Lithium-Ion Batteries

Abstract: 1T phase MoS2 possesses higher conductivity than the 2H phase, which is a key parameter of electrochemical performance for lithium ion batteries (LIBs). Herein, a 1T-MoS2 /C hybrid is successfully synthesized through facile hydrothermal method with a proper glucose additive. The synthesized hybrid material is composed of smaller and fewer-layer 1T-MoS2 nanosheets covered by thin carbon layers with an enlarged interlayer spacing of 0.94 nm. When it is used as an anode material for LIBs, the enlarged interlayer spacing facilitates rapid intercalating and deintercalating of lithium ions and accommodates volume change during cycling. The high intrinsic conductivity of 1T-MoS2 also contributes to a faster transfer of lithium ions and electrons. Moreover, much smaller and fewer-layer nanosheets can shorten the diffusion path of lithium ions and accelerate reaction kinetics, leading to an improved electrochemical performance. It delivers a high initial capacity of 920.6 mAh g-1 at 1 A g-1 and the capacity can maintain 870 mAh g-1 even after 300 cycles, showing a superior cycling stability. The electrode presents a high rate performance as well with a reversible capacity of 600 mAh g-1 at 10 A g-1 . These results show that the 1T-MoS2 /C hybrid shows potential for use in high-performance lithium-ion batteries.

Construction of hierarchical V4C3-MXene/MoS2/C nanohybrids for high rate lithium-ion batteries.

Abstract: MoS2 is a promising anode candidate for high-performance lithium-ion batteries (LIBs) due to its unique layered structure and high specific capacity. However, the poor conductivity and unsatisfactory structural stability limit its practical application. Recently, a new class of 2D materials, V4C3-Mxene, has been found to combine metallic conductivity, high structural stability and rich surface chemistries. Herein, a facile method has been developed to fabricate V4C3-MXene/MoS2/C nanohybrids. Ultrasmall and few-layered MoS2 nanosheets are uniformly anchored on the surface of V4C3-MXene with a thin carbon-coating layer. The ultrasmall and few-layered MoS2 nanosheets can enlarge the specific areas, reduce the diffusion distance of lithium ions, and accelerate the transfer of charge carriers. As a supporting substrate, V4C3-MXene endows the nanohybrid with high electrical conductivity, strong structural stability, and fast reaction kinetics. Moreover, the carbon-coating layer can further enhance the electrical conductivity and structural stability of the hybrid material. Benefiting from these advantages, the V4C3-MXene/MoS2/C electrode shows an excellent cycling stability with a high reversible capability of 622.6 mA h g-1 at 1 A g-1 after 450 cycles, and a superior rate capability of 500.0 mA h g-1 at 10 A g-1. Thus, the V4C3-MXene/MoS2/C nanohybrid could become a promising anode material for high rate LIBs.

Reentrant spin glass behavior and magnetodielectric coupling of an Ir-based double perovskite compound, La2CoIrO6.

Abstract: The structural, magnetic, electrical and dielectric properties of an Ir-based double perovskite compound, La2CoIrO6, have been investigated. The sample undergoes a paramagnetic-ferromagnetic transition at TC, followed by a reentrant spin-glass transition at lower temperatures. The reentrant spin glass state in La2CoIrO6 is associated with the competitions of the antiferromagnetic coupling between Ir4+ and Co2+ ions and the ferromagnetic clusters. La2CoIrO6 shows a semiconducting transport behavior in the temperature range 65 to 360 K and the transport behavior can be well described by the three-dimensional Mott variable range hopping conduction mechanism. Moreover, a strong frequency dependence of dielectric constant behavior for La2CoIrO6 is observed and the dielectric relaxation can be ascribed to the electron hopping between different transition metal ions. In addition, the isothermal magnetic field dependent dielectric constant measurements show that a clear magnetodielectric coupling effect exists in La2CoIrO6 at low temperatures.

Rational Design of Two-Dimensional Transition Metal Carbide/Nitride (MXene) Hybrids and Nanocomposites for Catalytic Energy Storage and Conversion

Abstract: Electro-, photo-, and photoelectrocatalysis play a critical role toward the realization of a sustainable energy economy. They facilitate numerous redox reactions in energy storage and conversion systems, enabling the production of chemical feedstock and clean fuels from abundant resources like water, carbon dioxide, and nitrogen. One major obstacle for their large-scale implementation is the scarcity of cost-effective, durable, and efficient catalysts. A family of two-dimensional transition metal carbides, nitrides, and carbonitrides (MXenes) has recently emerged as promising earth-abundant candidates for large-area catalytic energy storage and conversion due to their unique properties of hydrophilicity, high metallic conductivity, and ease of production by solution processing. To take full advantage of these desirable properties, MXenes have been combined with other materials to form MXene hybrids with significantly enhanced catalytic performances beyond the sum of their individual components. MXene hybridization tunes the electronic structure toward optimal binding of redox active species to improve intrinsic activity while increasing the density and accessibility of active sites. This review outlines recent strategies in the design of MXene hybrids for industrially relevant electrocatalytic, photocatalytic, and photoelectrocatalytic applications such as water splitting, metal-air/sulfur batteries, carbon dioxide reduction, and nitrogen reduction. By clarifying the roles of individual material components in the MXene hybrids, we provide design strategies to synergistically couple MXenes with associated materials for highly efficient and durable catalytic applications. We conclude by highlighting key gaps in the current understanding of MXene hybrids to guide future MXene hybrid designs in catalytic energy storage and conversion applications.

Advances in the Synthesis of 2D MXenes.

Abstract: 2D transition metal carbides, nitrides, and carbonitrides, also known as MXenes, are versatile materials due to their adjustable structure and rich surface chemistry. The physical and chemical diversity has recognized MXenes as a potential 2D material with a wide spectrum of application domains. Since the discovery of MXenes in 2011, a wide variety of synthetic routes has been proposed with advancement toward large-scale preparing methods for MXene nanosheets and derivative products. Herein, the critical synthesis aspects and the operating conditions that influence the physical and chemical characteristics of MXenes are discussed in detail. The emerging etching methods including HF etching methods, in situ HF-forming etching methods, electrochemical etching methods, alkali etching methods, and molten salt etching methods, as well as delamination strategies are discussed. Considering the future developments and practical applications, the large-scale synthesis routes and the antioxidation strategies of MXenes are also summarized. In summary, a generalized overview of MXenes synthesis protocols with an outlook for the current challenges and promising technologies for large-scale preparation and stable storage is provided.