Qingguo Chen

Bio: Qingguo Chen is an academic researcher from Harbin University of Science and Technology. The author has contributed to research in topics: Dielectric & Materials science. The author has an hindex of 13, co-authored 74 publications receiving 671 citations.

Sandwich-Structured PVDF-Based Composite Incorporated with Hybrid Fe3O4@BN Nanosheets for Excellent Dielectric Properties and Energy Storage Performance

Abstract: High-performance energy storage materials are of essential importance in advanced electronics and pulsed power systems, and the polymer dielectrics have been considered as a promising energy storage material, because of its higher dielectric strength and more excellent flexibility compared with that of inorganic ceramic dielectrics. However, the energy storage capability of pristine polymer has been limited by its low intrinsic dielectric permittivity and ordinary ferroelectric performance. Herein, this work demonstrates a favorable method to achieve a sandwich-structured poly(vinylidene fluoride) (PVDF)-based composite by the electrospinning, solution casting, thermal quenching, and hot-pressing process. This innovative method combines with the 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanofibers (BZT-BCT NFs), which possesses good ferroelectric hysteresis, and the hybrid particles of hexagonal boron nitride nanosheets (BNNSs) coated by ferroferric oxide (Fe3O4@BNNSs), which hold high breakdown strength (E...

Excellent Energy Storage Properties with High-Temperature Stability in Sandwich-Structured Polyimide-Based Composite Films

Abstract: In recent years, polymer-based dielectric capacitors have attracted much more attention due to the advantages of excellent flexibility, light weight, and high power density. However, most studies focus on energy storage performances of polymer-based dielectrics at room temperature, and there have been relatively fewer investigations on polymer-based dielectrics working under high-temperature conditions, which is much closer to the practical applications. Besides, dielectric capacitors operating in a high-temperature environment require excellent temperature stability of structure and performance. In this paper, high-temperature-resistant polyimide (PI) is selected as the matrix material, and 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BZT–BCT) nanofibers are used as the filling phase. By analyzing the energy storage behaviors of BZT–BCT/PI composites at different temperatures, it can be found that when the doping content of BZT–BCT nanofibers is more than 1 vol % the dielectric strength of the composites dro...

Coupling PEDOT on Mesoporous Vanadium Nitride Arrays for Advanced Flexible All‐Solid‐State Supercapacitors

Abstract: Tailored construction of advanced flexible supercapacitors (SCs) is of great importance to the development of high-performance wearable modern electronics. Herein, a facile combined wet chemical method to fabricate novel mesoporous vanadium nitride (VN) composite arrays coupled with poly(3,4-ethylenedioxythiophene) (PEDOT) as flexible electrodes for all-solid-state SCs is reported. The mesoporous VN nanosheets arrays prepared by the hydrothermal-nitridation method are composed of cross-linked nanoparticles of 10-50 nm. To enhance electrochemical stability, the VN is further coupled with electrodeposited PEDOT shell to form high-quality VN/PEDOT flexible arrays. Benefiting from high intrinsic reactivity and enhanced structural stability, the designed VN/PEDOT flexible arrays exhibit a high specific capacitance of 226.2 F g-1 at 1 A g-1 and an excellent cycle stability with 91.5% capacity retention after 5000 cycles at 10 A g-1 . In addition, high energy/power density (48.36 Wh kg-1 at 2 A g-1 and 4 kW kg-1 at 5 A g-1 ) and notable cycling life (91.6% retention over 10 000 cycles) are also achieved in the assembled asymmetric flexible supercapacitor cell with commercial nickel-cobalt-aluminum ternary oxides cathode and VN/PEDOT anode. This research opens up a way for construction of advanced hybrid organic-inorganic electrodes for flexible energy storage.

MoS2 Nanosheets Vertically Aligned on Carbon Paper: A Freestanding Electrode for Highly Reversible Sodium Ion Batteries

Abstract: The development of sodium-ion batteries for large-scale applications requires the synthesis of electrode materials with high capacity, high initial Coulombic efficiency (ICE), high rate performance, long cycle life, and low cost. A rational design of freestanding anode materials is reported for sodium-ion batteries, consisting of molybdenum disulfide (MoS2) nanosheets aligned vertically on carbon paper derived from paper towel. The hierarchical structure enables sufficient electrode/electrolyte interaction and fast electron transportation. Meanwhile, the unique architecture can minimize the excessive interface between carbon and electrolyte, enabling high ICE. The as-prepared MoS2@carbon paper composites as freestanding electrodes for sodium-ion batteries can liberate the traditional electrode manufacturing procedure, thereby reducing the cost of sodium-ion batteries. The freestanding MoS2@carbon paper electrode exhibits a high reversible capacity, high ICE, good cycling performance, and excellent rate capability. By exploiting in situ Raman spectroscopy, the reversibility of the phase transition from 2H-MoS2 to 1T-MoS2 is observed during the sodium-ion intercalation/deintercalation process. This work is expected to inspire the development of advanced electrode materials for high-performance sodium-ion batteries.

Strong Electromagnetic Wave Response Derived from the Construction of Dielectric/Magnetic Media Heterostructure and Multiple Interfaces.

Abstract: A novel yolk–shell structure of cobalt nanoparticle embedded nanoporous carbon@carbonyl iron (Co/NPC@Void@CI) was synthesized via metal organic chemical vapor deposition (MOCVD) and subsequent calcination treatment. The in situ generation of void layer, which originated from the shrink of a Co-based zeolitic imidazolate framework (ZIF-67) during carbonization, embodies distinct advantage compared to the conventional template method. Thanks to the introduction of custom-designed dielectric/magnetic media heterostructure and multiple interfaces, the composites filled with 40 wt % of Co/NPC@Void@CI samples in paraffin exhibit a maximum reflection loss of −49.2 dB at 2.2 mm; importantly, a broad absorption bandwidth (RL < −10 dB) of 6.72 GHz can be obtained, which covers more than one-third of the whole frequency region from 10.56 to 17.28 GHz. This study not only develops the application of carbonyl iron as a high-efficiency light absorber but also initiates a fire-new avenue for artificially designed hetero...