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97 results on '"Zheng, Junsheng"'

81. Fabrication of Dual‐Modified Carbon Network Enabling Improved Electronic and Ionic Conductivities for Fast and Durable Li2TiSiO5 Anodes.

Author

Jin, Liming, Gong, Ruiqi, Zheng, Junsheng, Zhang, Cunman, Xia, Yongyao, and Zheng, Jim P.

Subjects
ANODES, ENERGY density, LITHIUM-ion batteries, DIFFUSION, CATHODES
Abstract

Li2TiSiO5 was recently proposed as a Ti‐based anode material for lithium‐ion batteries (LIBs), with the desirable characteristics of low discharge potential and relatively high specific capacity. However, the intrinsically poor electronic and ionic conductivities give rise to its sluggish electrochemical performance. In this work, Li2TiSiO5 modified with a dual‐carbon network (C@LTSO/CNT) is developed by performing a facile synthesis. The obtained dual‐carbon network coupled with small‐sized LTSO particles delivers enhanced electron conductivity frameworks, abundant active interfaces, and a notably higher inner porosity for multidirectional ion diffusion. Such a unique architecture leads to a high specific capacity as well as an ultrafast electrochemical process for LTSO through remarkable electronic and ionic transfer. C@LTSO/CNT electrodes with a low discharge plateau at 0.28 V achieve an extremely competitive specific capacity of over 430 mAh g−1 at 0.5 C, a superb high‐rate performance over 125 mAh g−1 up to 10 C, and a stable cycle lifespan of 1500 cycles without any degradation, displaying significant potential as an ideal anode candidate. Thus, a high‐performance LIB full cell is fabricated with a C@LTSO/CNT anode and a LiFePO4 cathode. This cell shows an energy density of 200 Wh kg−1 with greatly improved properties of high‐power density and pronounced cycling stability. [ABSTRACT FROM AUTHOR]

Published
2019
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82. Toward high energy-density and long cycling-lifespan lithium ion capacitors: a 3D carbon modified low-potential Li2TiSiO5 anode coupled with a lignin-derived activated carbon cathode.

Author

Jin, Liming, Gong, Ruiqi, Zhang, Weichao, Xiang, Yue, Zheng, Junsheng, Xiang, Zhonghua, Zhang, Cunman, Xia, Yongyao, and Zheng, Jim P.

Abstract

Lithium ion capacitors (LIC), which can bridge the gap between lithium ion batteries and supercapacitors by combining the merits of the two systems, are thus considered as some of the most promising energy storage devices. However, the imbalances in specific capacity, high-rate behavior, and cycling lifespan between the two electrodes make it a challenge to develop LICs with high energy density at high power density output along with long cycle life. Herein, a LIC consisting of a three-dimensional carbon modified LTSO (3DC@LTSO) anode and a lignin-derived activated carbon (LDAC) cathode is designed and fabricated. These two electrode materials with desirable electrochemical properties will much favorably offset the imbalances between the two electrodes. Moreover, a novel electrode-matching strategic approach, which will further offset the imbalance between the two electrodes, is developed. Thereby, the assembled LDAC//3DC@LTSO LIC cell shows a high energy density of 115.3 W h kg−1 at 163.5 W kg−1 and a high power density of 6560 W kg−1 at 60 W h kg−1, coupled with an excellent cycling lifespan of 90% capacity retention after 6000 cycles at a current density of 2.0 A g−1. These combined results are impressive in terms of obtaining high energy density and long cycling lifespan LICs. [ABSTRACT FROM AUTHOR]

Published
2019
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88. Hollow cubic double layer structured Cu7S4/NiS nanocomposites for high-performance supercapacitors.

Author

Cao, Hongliang, Wang, Xiang, Chen, Xin, Liu, Haiyang, Zheng, Junsheng, and Zhou, Wangfan

Abstract

A double layer hollow structured Cu7S4/NiS material is synthesized using a self-generated sacrificial template method, as an electrode material for supercapacitors. Cu7S4/NiS composites with three different particle sizes are synthesized and tested, which exhibited high specific capacitances of 1204 F g−1, 1028 F g−1 and 857 F g−1, respectively, at a current density of 1 A g−1. The specific capacitance of the nanocomposites remained at 945.5 F g−1 (85.8%), 719.2 F g−1 (84.32%) and 558.5 F g−1 (80.13%) levels after 1000 cycles, respectively, at a current density of 4 A g−1, showing good cycle stability. Compared with the pure NiS and Cu7S4, the development of the hollow Cu7S4/NiS composites is demonstrated to be effective in enhancing the supercapacitive performance. [ABSTRACT FROM AUTHOR]

Published
2017
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91. Study on carbon matrix composite bipolar plates with balance of conductivity and flexural strength

Author

Zheng, Junsheng, Peng, Yuhang, Fan, Runlin, Chen, Jing, Zhan, Zize, Yao, Dongmei, and Ming, Pingwen

Abstract

In order to balance the conductivity and flexural strength of graphite composite bipolar plates, the influence of conductive filler on the properties of graphite composite bipolar plate was comprehensively studied by using phenolic resin as binder, natural flake graphite as conductive substrate and functional carbon materials with different structures as auxiliary filler. The results show that the particle size of conductive substrate has an important influence on the conductivity enhancement of auxiliary filler. The influence of conductive particle size on auxiliary filler electrical conductivity improvement was first investigated in this research. The effects of various auxiliary filler concentrations on improving electrical conductivity and flexural strength were then examined. This research has substantial implications for the balance of electrical conductivity and flexural strength of graphite composite bipolar plates.

Published
2023
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94. Fast Fabrication of WS2/Bi2Se3Heterostructures for High-Performance Photodetection

Author

Li, Fan, Li, Jialin, Zheng, Junsheng, Tong, Yuanbiao, Zhu, Huanfeng, Wang, Pan, and Li, Linjun

Abstract

Two-dimensional (2D) material heterostructures have attracted considerable attention owing to their interesting and novel physical properties, which expand the possibilities for future optoelectronic, photovoltaic, and nanoelectronic applications. A portable, fast, and deterministic transfer technique is highly needed for the fabrication of heterostructures. Herein, we report a fast half-wet poly(dimethylsiloxane) (PDMS) transfer process utilizing the change of adhesion energy with the help of micron-sized water droplets. Using this method, a vertical stacking of the WS2/Bi2Se3heterostructure with a straddling band configuration is successfully assembled on a fluorophlogopite substrate. Thanks to the complementary band gaps and high efficiency of interfacial charge transfer, the photodetector based on the heterostructure exhibits a superior responsivity of 109.9 A W–1for a visible incident light at 473 nm and 26.7 A W–1for a 1064 nm near-infrared illumination. Such high photoresponsivity of the heterostructure demonstrates that our transfer method not only owns time efficiency but also ensures high quality of the heterointerface. Our study may open new pathways to the fast and massive fabrication of various vertical 2D heterostructures for applications in twistronics/valleytronics and other band engineering devices.

Published
2023
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95. (Digital Presentation) Development of Composite Graphite Plate with Multiple Functional Layers for Pemfc

Author

Fan, Runlin, Zheng, Junsheng, Chen, Jing, and Peng, Yuhang

Abstract

The bipolar plate is an important component of the proton exchange membrane fuel cell (PEMFC) and composite graphite bipolar plates (CGBPs) have attracted interest due to competitive benefits. However, their mechanical and electrical qualities are insufficient to meet the PEMFC's standards. In this study, a structural design of CGBPs with different functional layers was proposed. The surface layer was molded graphite plate with resin infiltration treatment, and the middle layer was a carbon fiber fabric (CFF) as a reinforcing functional layer. The results showed that the surface layer prepared from flake graphite possessed denser structure, leading to higher airtightness and structural strength. The addition of carbon nanotube or graphene nanoplate could enhance the combination between CFF and resin observably, making CGBPs possessed an in-plane conductivity of 446 S/cm, an area specific resistance of 6.4 mΩ·cm2, a flexural strength of 72 MPa, and a Helium permeability of around 4.4×10-6 std cm3/cm2·s.

Published
2022
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96. Comparative Study of the Power Performance for Advanced Li-Ion Capacitors with Various Carbon Anodes

Author

Cao, Wanjun, Zheng, Junsheng, Adams, Daniel, and Zheng, Jim P.

Abstract

In recent years, an increased attention has been focused on Li-ion capacitors (LICs) which are high power hybrid devices. Various carbon materials (hard carbon (HC), soft carbon (SC) and graphite) have been investigated for use as the negative electrodes for LICs. The rate capabilities are compared by half cells with carbon anode as working electrode and lithium foil as counter electrode, and by LIC full cells with test current density up to 20 mA cm-2. It is found that the LIC with HC at 20 mA cm-2 could be maintained up to 72.5% of that at 0.5 mA cm-2, which is the best power performance among all the carbon materials. The Scanning electron microscopy (SEM) images, surface area and the pore size distribution are also studied and compared for the various carbon anode materials.

Published
2014

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