Browsing by Author "Wei, Bingqing"
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Item An all-copper plasmonic sandwich system obtained through directly depositing copper NPs on a CVD grown graphene/copper film and its application in SERS(Royal Society of Chemistry, 2015-05-11) Li, Xuanhua; Ren, Xingang; Zhang, Yongxing; Choy, Wallace C. H.; Wei, Bingqing; Xuanhua Li, Xingang Ren, Yongxing Zhang, Wallace C. H. Choy and Bingqing Wei; Wei, BingqingA simple, low-cost, all-copper sandwich system has been obtained through directly depositing Cu nanoparticles (NPs) onto a graphene sheet, which has already been grown on a Cu foil (Cu-NGF). The new design inherits two key advantages: (1) the materials of the NGF coupling system are composed of only cheaper Cu instead of Au and Ag, (2) direct fabrication of the system without transferring graphene will greatly lower the fabrication cost. More importantly, the Cu-NFG system shows a high sensitivity in surface-enhanced Raman scattering (SERS) with the highest enhancement factor (EF, over 1.89 × 107) reported to date in Cu plasmonic systems. Experimental and theoretical results reveal that the strong EF is mainly because of the strong near-field coupling between Cu NPs and Cu films at the optimal angle of incidence, opening up a new route for Cu materials in SERS applications.Item Assembling metal-polyphenol coordination interfaces for longstanding zinc metal anodes(EcoMat, 2022-01-11) Huyan, Yu; Wang, Jian-Gan; Tian, Shan; Ren, Lingbo; Liu, Huanyan; Wei, BingqingZn metals have gained the immense attention of researchers for their wide employment as the anode of high-performance aqueous batteries. Nonetheless, the Zn anodes suffer from uncontrollable dendrite growth and parasitic side reactions, which substantially shorten the battery lifespan. This study proposes an interfacial assembly of a metal-polyphenol coordination coating on Zn anodes to regulate Zn2+ deposition behavior. Bismush-coordinated polyphenolic ligands (i.e., tannic acid, TA) create a functional interface that could promote Zn's uniform nucleation and plating/striping kinetics. Moreover, the artificial coating acts as a physical barrier to inhibit surface corrosion. As a consequence, the TA-Bi-modified Zn anodes display a small voltage hysteresis of ~38 mV at 1 mA cm−2 over 2600 h and an ultra-long lifespan for 3100 h (~4.3 months) even at a high-current density of 10 mA cm−2. When assembled with a vanadium-based cathode, the full Zn-ion batteries achieve improved electrochemical performance.Item Blending poly(2-ethyl-2-oxazoline) with hydrophobic polymers as a hybrid adhesive with enhanced water-resistant properties(Journal of Applied Polymer Science, 2021-07-16) Zhang, Yuanyuan; Li, Xuanhua; Guo, Shaohui; Wei, BingqingThe use of poly(2-ethyl-2-oxazoline) (PEOX) in a wet environment is limited because of its high hydrophilicity. In this study, PEOX based blends were prepared via blending PEOX with hydrophobic polymers, such as poly(styrene-co-acrylonitrile) (SAN), poly(4-vinylphenol) (PVPh), and poly(vinylidene fluoride) (PVDF), in order to improve the water-resistance of PEOX. The blends' water resistance properties are evaluated by the contact angle, solubility, moisture absorption, and mechanical strength in a wet environment. The results show that the water resistance and the adhesion strength of PEOX in a wet environment are dramatically enhanced by polymer blending. The blend with 30 wt% PVPh demonstrates excellent performances in transparency and water-resistant abilities. It is found that the stable hydrogen bonding within the blend plays an important role in hydrophobic modification. The PVPh/PEOX blend can be applied as a new type of transparent coating or adhesive with enhanced water-resistant properties in a wet environment.Item Boosting photocatalytic hydrogen production from water by photothermally induced biphase systems(Nature Communications, 2021-02-26) Guo, Shaohui; Li, Xuanhua; Li, Ju; Wei, BingqingSolar-driven hydrogen production from water using particulate photocatalysts is considered the most economical and effective approach to produce hydrogen fuel with little environmental concern. However, the efficiency of hydrogen production from water in particulate photocatalysis systems is still low. Here, we propose an efficient biphase photocatalytic system composed of integrated photothermal–photocatalytic materials that use charred wood substrates to convert liquid water to water steam, simultaneously splitting hydrogen under light illumination without additional energy. The photothermal–photocatalytic system exhibits biphase interfaces of photothermally-generated steam/photocatalyst/hydrogen, which significantly reduce the interface barrier and drastically lower the transport resistance of the hydrogen gas by nearly two orders of magnitude. In this work, an impressive hydrogen production rate up to 220.74 μmol h−1 cm−2 in the particulate photocatalytic systems has been achieved based on the wood/CoO system, demonstrating that the photothermal–photocatalytic biphase system is cost-effective and greatly advantageous for practical applications.Item Catalytic Boosting Bidirectional Polysulfide Redox using Co0.85Se/C Hollow Structure for High-Performance Lithium-Sulfur Batteries(ChemElectroChem, 2022-02-17) Zhang, Xingyuan; Gu, Honghui; Shen, Chao; Wei, Bingqing; Wang, Jian-GanAchieving effective adsorption and fast conversion of soluble polysulfides confined in the sulfur cathode is critical yet challenging for building high-performance lithium-sulfur batteries. Herein, we construct a unique hollow-structured Co0.85Se/C as a separator modifier (CSPP) to effectively suppress the polysulfide shuttle effect. The Co0.85Se/C demonstrates strong anchoring with polysulfide species and smooth bidirectional electrocatalysis. The unique mesoporous hollow architecture affords sufficient catalytic sites and Li+ diffusion channels for promoting the reaction kinetics. Benefiting from the merits, the CSPP-cell could yield a superior electrochemical utilization of active sulfur, excellent rate capability (679 mAh g−1 at 5 C), and stable cycling performance with an ultralow fading rate of 0.056 % per cycle over 500 cycles. The work highlights great promise of developing cobalt-based materials as kinetic regulators for highly stable lithium-sulfur batteries.Item Coaxial MoS2@Carbon Hybrid Fibers: A Low-Cost Anode Material for High-Performance Li-Ion Batteries(MDPI AG, 2017-02-13) Zhou, Rui; Wang, Jian-Gan; Liu, Hongzhen; Liu, Huanyan; Jin, Dandan; Liu, Xingrui; Shen, Chao; Xie, Keyu; Wei, Bingqing; Rui Zhou, Jian-GanWang, Hongzhen Liu, Huanyan Liu, Dandan Jin, Xingrui Liu, Chao Shen, Keyu Xie and Bingqing Wei; Wei, BingqingA low-cost bio-mass-derived carbon substrate has been employed to synthesize MoS2@carbon composites through a hydrothermal method. Carbon fibers derived from natural cotton provide a three-dimensional and open framework for the uniform growth of MoS2 nanosheets, thus hierarchically constructing coaxial architecture. The unique structure could synergistically benefit fast Li-ion and electron transport from the conductive carbon scaffold and porous MoS2 nanostructures. As a result, the MoS2@carbon composites—when serving as anodes for Li-ion batteries—exhibit a high reversible specific capacity of 820 mAh·g−1, high-rate capability (457 mAh·g−1 at 2 A·g−1), and excellent cycling stability. The use of bio-mass-derived carbon makes the MoS2@carbon composites low-cost and promising anode materials for high-performance Li-ion batteries.Item Expanded graphite embedded with aluminum nanoparticles as superior thermal conductivity anodes for high-performance lithium-ion batteries(Nature Publishing Group, 9/27/16) Zhao,Tingkai; She,Shengfei; Ji,Xianglin; Guo,Xinai; Jin,Wenbo; Zhu,Ruoxing; Dang,Alei; Li,Hao; Li,Tiehu; Wei,Bingqing; Tingkai Zhao,Shengfei She, Xianglin Ji, Xinai Guo, Wenbo Jin, Ruoxing Zhu, Alei Dang, Hao Li, Tiehu Li and Bingqing Wei; Wei, BingqingThe Developmentelopment of high capacity and long-life lithium-ion batteries is a long-term pursuing and under a close scrutiny. Most of the researches have been focused on exploring electrode materials and structures with high store capability of lithium ions and at the same time with a good electrical conductivity. Thermal conductivity of an electrode material will also have significant impacts on boosting battery capacity and prolonging battery lifetime, which is, however, underestimated. Here, we present the Developmentelopment of an expanded graphite embedded with Al metal nanoparticles (EG-MNPs-Al) synthesized by an oxidation-expansion process. The synthesized EG-MNPs-Al material exhibited a typical hierarchical structure with embedded Al metal nanoparticles into the interspaces of expanded graphite. The parallel thermal conductivity was up to 11.6 W.m(-1).K-1 with a bulk density of 453 kg.m(-3) at room temperature, a 150% improvement compared to expanded graphite (4.6 W.m(-1).K-1) owing to the existence of Al metal nanoparticles. The first reversible capacity of EG-MNPs-Al as anode material for lithium ion battery was 480 mAh.g(-1) at a current density of 100 mA.g(-1), and retained 84% capacity after 300 cycles. The improved cycling stability and system security of lithium ion batteries is attributed to the excellent thermal conductivity of the EG-MNPs-Al anodes.Item Facile Synthesis of V2O5 Hollow Spheres as Advanced Cathodes for High-Performance Lithium-Ion Batteries(MDPI, 2017-01-18) Zhang, Xingyuan; Wang, Jian-Gan; Liu, Huanyan; Liu, Hongzhen; Wei, Bingqing; Xingyuan Zhang, Jian-GanWang, Huanyan Liu, Hongzhen Liu and Bingqing Wei; Wei, BingqingThree-dimensional V2O5 hollow structures have been prepared through a simple synthesis strategy combining solvothermal treatment and a subsequent thermal annealing. The V2O5 materials are composed of microspheres 2–3 m in diameter and with a distinct hollow interior. The as-synthesized V2O5 hollow microspheres, when evaluated as a cathode material for lithium-ion batteries, can deliver a specific capacity as high as 273 mAh g���1 at 0.2 C. Benefiting from the hollow structures that afford fast electrolyte transport and volume accommodation, the V2O5 cathode also exhibits a superior rate capability and excellent cycling stability. The good Li-ion storage performance demonstrates the great potential of this unique V2O5 hollow material as a high-performance cathode for lithium-ion batteries.Item Fast and stable redox reactions of MnO2/CNT hybrid electrodes for dynamically stretchable pseudocapacitors(Royal Society of Chemistry, 2015-06-04) Gu, Taoli; Wei, Bingqing; Taoli Gu and Bingqing Wei; Gu, Taoli; Wei, BingqingPseudocapacitors, which are energy storage devices that take advantage of redox reactions to store electricity, have a different charge storage mechanism compared to lithium-ion batteries (LIBs) and electric double-layer capacitors (EDLCs), and they could realize further gains if they were used as stretchable power sources. The realization of dynamically stretchable pseudocapacitors and understanding of the underlying fundamentals of their mechanical–electrochemical relationship have become indispensable. We report herein the electrochemical performance of dynamically stretchable pseudocapacitors using buckled MnO2/CNT hybrid electrodes. The extremely small relaxation time constant of less than 0.15 s indicates a fast redox reaction at the MnO2/CNT hybrid electrodes, securing a stable electrochemical performance for the dynamically stretchable pseudocapacitors. This finding and the fundamental understanding gained from the pseudo-capacitive behavior coupled with mechanical deformation under a dynamic stretching mode would provide guidance to further improve their overall performance including a higher power density than LIBs, a higher energy density than EDLCs, and a long-life cycling stability. Most importantly, these results will potentially accelerate the applications of stretchable pseudocapacitors for flexible and biomedical electronics.Item Near Zero-Threshold Voltage P-N Junction Diodes Based on Super-Semiconducting Nanostructured Ag/Al Arrays(Advanced Materials, 2023-03-29) Li, Zhigang; Li, Jiteng; Wang, Weike; Yan, Qijie; Zhou, Yongrui; Zhu, Luping; Cao, Bingqiang; Wei, BingqingSemiconductor devices are currently one of the most common energy consumption devices. Significantly reducing the energy consumption of semiconductor devices with advanced energy-efficient technologies is highly desirable. The discovery of super-semiconductors (SSCs) based on metallic bi-layer shell arrays provides an opportunity to realize ultra-low-power consumption semiconductor devices. As an example, the achievement of near zero-threshold voltage in p-n junction diodes based on super-semiconducting nanostructured Ag/Al arrays is reported, realizing ultra-low-power p-n junction diodes: ≈3 W per trillion diodes with a working voltage of 1 V or 30 mW per trillion diodes with an operating voltage of 0.1 V. In addition, the p-n junction diodes exhibit a high breakdown field of ≈1.1 × 106 V cm−1, similar to that of SiC and GaN, due to a robust built-in field driven by infrared light photons. The SSC p-n diodes with near zero-threshold voltage and high breakdown field allow access to ultra-low-power semiconducting transistors, integrated circuits, chips, etc.Item Non-Monotonic Capacitance Change of Layered Ti3C2Tx MXene Film Structures under Increasing Compressive Stress(Advanced Functional Materials, 2022-12-09) Zhang, Qing; Ning, Ran; Cao, Jinxin; Song, Qingrui; Ye, Jiaxin; Wei, BingqingThe progress in advanced electronic devices has imposed a great demand for developing flexible electrochemical power devices, which requires a comprehensive understanding of the mechanical–electrochemical coupling behavior of various energy storage materials. Unlike a monotonic capacitance increase of carbon-based double-layer supercapacitors, MXene-based flexible supercapacitors demonstrate a non-monotonic, i.e., “increase-then-decrease” capacitance behavior under the pressure range of 8488 kPa. This non-monotonic capacitance response to pressure is intrinsic to the MXene film as its charge storage is primarily determined by the surface activity, which can be readily affected by pressure-induced dissociation of functionalities, as well as the charge transporting kinetics as limited by the inherent layered structure. The findings described in this study not only expand the knowledge of mechanical–electrochemical coupling to layered MXenes under pressure, but also give a vital design guideline for flexible/stretchable MXene-based energy storage devices or other electronics.Item Plasma-Wind-Assisted In2S3 Preparation with an Amorphous Surface Structure for Enhanced Photocatalytic Hydrogen Production(Nanomaterials, 2022-05-21) Guo, Shaohui; Luo, Hui; Duan, Xiaochuan; Wei, Bingqing; Zhang, XianmingPhotocatalytic production from water is considered an effective solution to fossil fuel-related environmental concerns, and photocatalyst surface science holds a significant interest in balancing photocatalysts’ stability and activity. We propose a plasma-wind method to tune the surface properties of a photocatalyst with an amorphous structure. Theoretical calculation shows that the amorphous surface structure can cause an unsaturated coordination environment to adjust the electron distribution, forming more adsorption sites. Thus, the photocatalyst with a crystal–amorphous (C–A) interface can strengthen light absorption, harvest photo-induced electrons, and enrich the active sites, which help improve hydrogen yield. As a proof of concept, with indium sulfide (In2S3) nanosheets used as the catalyst, an impressive hydrogen production rate up to 457.35 μmol cm−2 h−1 has been achieved. Moreover, after plasma-assisted treatment, In2S3 with a C–A interface can produce hydrogen from water under natural outdoor conditions. Following a six-hour test, the rate of photocatalytic hydrogen evolution is found to be 400.50 μmol cm−2 g−1, which demonstrates that a catalyst prepared through plasma treatment is both effective and highly practical.Item Plasmon-induced super-semiconductor at room temperature in nanostructured bimetallic arrays(Applied Physics Reviews, 2022-05-17) Li, Zhigang; Cui, Xiangke; Wang, Xiaowei; Wang, Zongpeng; Fang, Minghu; Feng, Shangshen; Liu, Yanping; Chen, Jigen; Wang, Tianle; Liu, Hengji; Xia, Zhenhai; Wei, BingqingSolid-state electrical conducting materials can be roughly categorized as superconductors, conductors, and semiconductors, depending on their conducting carriers, resistance, and band structures. This research reports the discovery of super-semiconductors, whose resistivity is 3–10 orders of magnitude lower than conventional semiconductors at room temperature. In addition, there is a transition from a metal state to a super-semiconducting state at near room temperatures, which is accompanied by an increase in hole carrier density and the mobility increase in electrons. For the first time, a hole-dominated carrier metal is observed in nanostructured bimetallic arrays near room temperature, and no other special conditions are required. Such a behavior is due to the generation of hot electrons and holes induced by metal plasmon resonance in the infrared range in the nanostructured bimetallic arrays. Our research empowers metals with semiconductor features and paves the way to realize ultra-low-power metal-based semiconductor devices.Item Synthesis of ultralong MnO/C coaxial nanowires as freestanding anodes for high-performance lithium ion batteries(Royal Society of Chemistry, 2015-05-20) Wang, Jian-Gan; Zhang, Cunbao; Jin, Dandan; Xie, Keyu; Wei, Bingqing; Jian-Gan Wang, Cunbao Zhang, Dandan Jin, Keyu Xie and Bingqing Wei; Wei, BingqingA facile synthesis strategy is reported for the preparation of a freestanding membrane of ultralong MnO/C coaxial nanowires using a novel in situ interfacial polymerization technique. The MnO/C membrane possesses interconnected porous structures with a nanowire diameter of ca. 100 nm and a length of up to hundreds of micrometers. When used as a freestanding anode for lithium ion batteries, the coaxial MnO/C nanocomposites exhibit a high reversible capacity of 832 mA h g−1 at a current density of 100 mA g−1 after 100 cycles, good rate capability and outstanding cycling stability with a specific capacity of 480 mA h g−1 being retained after 600 cycles at a high current density of 1000 mA g−1. The uniform carbon coating formed along the ultralong one-dimensional nanostructure surface is the key-enabling factor that not only improves the electrode reaction kinetics, but also renders excellent cycling performance by accommodating the large volume variation of MnO during charge/discharge processes. The superior electrochemical properties suggest that the facile synthesis strategy can be extended to the fabrication of other freestanding films for potential application in energy storage systems.Item TiO2 enhanced ultraviolet detection based on a graphene/Si Schottky diode(Royal Society of Chemistry., 2015-03-11) Zhu, Miao; Zhang, Li; Li, Xinming; He, Yijia; Li, Xiao; Guo, Fengmei; Zang, Xiaobei; Wang, Kunlin; Xie, Dan; Li, Xuanhua; Wei, Bingqing; Zhu, Hongwei; Miao Zhu, Li Zhang, Xinming Li, Yijia He, Xiao Li, Fengmei Guo, Xiaobei Zang, Kunlin Wang, Dan Xie, Xuanhua Li, Bingqing Wei and Hongwei Zhu; Wei, BingqingGraphene/Si has been proved to form a quality Schottky junction with high photoelectric conversion efficiency at AM 1.5. However, for the ultraviolet portion of the incident light, the photoelectric performance will degrade significantly due to severe absorption and recombination at the front surface. Herein, to realize enhanced ultraviolet detection with a graphene/Si diode, TiO2 nanoparticles (NPs, 3–5 nm) are synthesized and spin-coated on the graphene surface to improve the photoresponse in the ultraviolet region. According to our results, the conversion efficiency of the graphene/Si diode at 420 nm and 350 nm increases by 72.7% and 100% respectively with TiO2 coating. Then C−2–V measurements of both TiO2 and graphene/Si diode are performed to analyze the electronic band structure of the TiO2/graphene/Si system, based on which we finally present the enhancement mechanism of photodetection using TiO2 NPs.Item Understanding the nanoscale local buckling behavior of vertically aligned MWCNT arrays with van der Waals interactions(Royal Society of Chemistry, 2015-07-20) Li, Yupeng; Kim, Hyung-ick; Wei, Bingqing; Kang, Junmo; Choi, Jae-boong; Nam, Jae-Do; Suhr, Jonghwan; Yupeng Li, Hyung-ick Kim, Bingqing Wei, Junmo Kang, Jae-boong Choi, Jae-Do Nam and Jonghwan Suhr; Li, Yupeng; Wei, BingqingThe local buckling behavior of vertically aligned carbon nanotubes (VACNTs) has been investigated and interpreted in the view of a collective nanotube response by taking van der Waals interactions into account. To the best of our knowledge, this is the first report on the case of collective VACNT behavior regarding van der Waals force among nanotubes as a lateral support effect during the buckling process. The local buckling propagation and development of VACNTs were experimentally observed and theoretically analyzed by employing finite element modeling with lateral support from van der Waals interactions among nanotubes. Both experimental and theoretical analyses show that VACNTs buckled in the bottom region with many short waves and almost identical wavelengths, indicating a high mode buckling. Furthermore, the propagation and development mechanism of buckling waves follow the wave damping effect.