Dongguan Mcnair Technology Co.

Dongguan, China

Dongguan Mcnair Technology Co.

Dongguan, China
SEARCH FILTERS
Time filter
Source Type

Zeng J.,Harbin Institute of Technology | Liu Y.,Harbin Institute of Technology | Wu J.,Harbin Institute of Technology | Cui Y.,Harbin Institute of Technology | And 6 more authors.
Electrochimica Acta | Year: 2017

Lithium rich oxides have over recent years attracted significant attention as materials able to exhibit high electrical capacity, despite, they exhibit poor rate capability and unstable cycling performance. In this paper, layered lithium rich oxide, Li1.2Mn0.54Ni0.13Co0.13O2 is prepared by solvothermal method and then it is protected by a coating consisting of spinel LixMn1.5Ni0.5O4 giving rise to a series of spinel/layered heterostructured materials. The results conrfim that the presence of spinel coating offers the 3D pathways for the diffusion of lithium ions and assures long-lasting performances of the resulting cathode materials. In particular the heterostructured materials modified with 2 wt% LixMn1.5Ni0.5O4 amount exhibits the highest specific capacity (over 264 mAh g−1 at current density of 40 mA g−1, comparing to 237 mAh g−1 for the pristine layered structured material), excellent initial coulombic efficiency (82%), optimal cycling performance (capacity retention of 94% after 100 cycles at current density of 200 mA g−1) and outstanding rate capability with enhanced lithium diffusion coefficient (7.13 × 10−13 cm−1s−1 of 2 wt% coating amount is much higher than that of 4.23 × 10−13 cm−1s−1 for pristine material electrode). The finding reported in this work provides a novel insight into the design and preparation of high-performance spinel/layered heterostructured materials. © 2017 Elsevier Ltd


Cui Y.,Harbin Institute of Technology | Wu X.,Peking University Shenzhen Graduate School | Wu J.,Harbin Institute of Technology | Zeng J.,Harbin Institute of Technology | And 8 more authors.
Energy Storage Materials | Year: 2017

A carbonized interlayer is effective for enhancing the electrochemical performance of a lithium sulfur (Li-S) battery. Here we report on two different interlayer architectures which are derived from cotton using simple preparation processes. One is a large pore volume carbon matrix (LCM) and the other is a porous carbon matrix with undulating zones partially covering the surface (UCM). These two interlayers are anticipated to restrain the shuttle effect of lithium polysulfides and improve the cycling stability. The LCM can be impregnated with 74.5 wt% sulfur and this is also used as the cathode for a Li-S battery. The electrochemical results show that cathode with UCM as the interlayer is superior with excellent cycling stability at 0.5 C and a specific capacity of 691 mAh g−1 after the 300th cycle. Even at 5.55 mg cm−2 sulfur loading the cathode with UCM interlayer can obtain an areal capacity of 3.2 mAh cm−2 at the 180th cycle. The method developed here is practical for the large-scale production of LCM and UCM interlayers for use in Li-S batteries. © 2017


Zeng J.,Harbin Institute of Technology | Cui Y.,Harbin Institute of Technology | Qu D.,University of Wisconsin - Milwaukee | Qu D.,Dongguan Mcnair Technology Co. | And 5 more authors.
ACS Applied Materials and Interfaces | Year: 2016

Lithium-rich layered oxides are promising cathode candidates for the production of high-energy and high-power electronic devices with high specific capacity and high discharge voltage. However, unstable cycling performance, especially at high charge-recharge rate, is the most challenge issue which needs to be solved to foster the diffusion of these materials. In this paper, hierarchical platelike Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials were synthesized by a facile solvothermal method followed by calcination. Calcination time was found to be a key parameter to obtain pure layered oxide phase and tailor its hierarchical morphology. The Li-rich material consists of primary nanoparticles with exposed {010} planes assembled to form platelike layers which exhibit low resistance to Li+ diffusion. In detail, the product by calcination at 900 °C for 12 h exhibits specific capacity of 228, 218, and 204 mA h g-1 at 200, 400, and 1000 mA g-1, respectively, whereas after 100 cycles at 1000 mA g-1 rate of charge and recharge the specific capacity was retained by about 91%. © 2016 American Chemical Society.


Cui Y.,Harbin Institute of Technology | Liang X.,Harbin Institute of Technology | Ouyang J.,Harbin Institute of Technology | Huang J.,Harbin Institute of Technology | And 8 more authors.
RSC Advances | Year: 2016

A novel sulfur-impregnated porous carbon matrix (PCM-Z-S) has been prepared as a cathode material for a lithium-sulfur battery. The porous carbon matrix (PCM-Z), which was obtained using de-waxed cotton and ZnCl2 as an activator, has a surface area of 1056 m2 g-1 and a pore volume of 1.75 cm3 g-1. The PCM-Z was mixed with sublimed sulfur and then heated in nitrogen gas to form a carbon-sulfur 58 wt% composite (PCM-Z-S) which has excellent electrochemical proprieties. The PCM-Z-S delivers a capacity of 850 mA h g-1 at 1C and retains 630 mA h g-1 after nearly 200 cycles which are values much higher than that of a carbon matrix prepared without ZnCl2. These results show the sulfur-impregnated porous carbon matrix (PCM-Z-S) has great potential as a cathode material in a lithium-sulfur battery. © 2016 The Royal Society of Chemistry.


Deng L.,Harbin Institute of Technology | Cui Y.,Harbin Institute of Technology | Chen J.,Harbin Institute of Technology | Wu J.,Harbin Institute of Technology | And 3 more authors.
Electrochimica Acta | Year: 2016

A Si-based alloy as the anode material in Li-ion batteries has advantages of safety and excellent performances, but poor electronic conductivity and excessive volume expansion limit the long cycle life required for practical application. In this work, in order to solve these problems, a core-shell nanocomposite has been developed, which is composed of a Si core and NiSi2/Ni shell with a carbon layer coating as the outer surface, which is referred to as a Si@NiSi2/Ni/C nanocomposite. Results show a reversible charge capacity of 1194 mA h g-1 and 98% retention after 105 cycles, which are superior to its Si/C and NiSi2/Si counterparts. Furthermore, the fabrication method used has advantages of low cost and easy operation, which make it feasible to commercialize the Si@NiSi2/Ni/C nanocomposite as the anode in a lithium-ion battery. © 2016 Elsevier Ltd. All rights reserved.


Wei Z.,Harbin Institute of Technology | Cui Y.,Harbin Institute of Technology | Huang K.,University of South Carolina | Ouyang J.,Harbin Institute of Technology | And 3 more authors.
RSC Advances | Year: 2016

Efficient catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are crucial enabling materials for rechargeable Li-O2 batteries. In the present work, La2NiO4 (LNO) synthesized by a hydrothermal process and modified Pechini method were studied as catalysts for rechargeable Li-O2 batteries. The catalyst prepared by the hydrothermal method shows a smaller particle size and a macroporous structure with 10× higher surface area than that synthesized by the Pechini counterpart, leading to a better electrocatalytic activity. The improved OER catalytic activity of the hydrothermal-LNO nanoparticles was confirmed by a 150 mV lower recharge potential than the Pechini-LNO particles and catalyst-free pure Super P (SP) electrode. In addition, the hydrothermal-LNO catalyzed battery cell delivered a first discharge capacity of 14 310.9 mA h g-1 at 0.16 mA cm-2, compared to 8132.4 mA h g-1 of the Pechini-LNO and 7478.8 mA h g-1 of the pure SP electrode, demonstrating higher catalytic ORR activity of the hydrothermal-LNO particles. Overall, the LNO nanoparticles are a promising cathode catalyst for non-aqueous electrolyte based Li-O2 batteries. © The Royal Society of Chemistry 2016.


He F.,Harbin Institute of Technology | Wang X.,Tianjin Polytechnic University | Du C.,Tianjin University | Baker A.P.,Harbin Institute of Technology | And 2 more authors.
Electrochimica Acta | Year: 2015

The lithium-rich layered oxide; xLi2MnO3•(1-x)LiMeO2 (Me = Co, Ni, Mn, etc.) is one of the most promising cathode materials for lithium-ion batteries in electric vehicles and energy storage systems due to its high energy density, low cost, and excellent thermal stability. In this work, Li1.2Ni0.13Co0.13Mn0.54O2 was synthesized and novel coating was applied to enhance the performance. The pristine Li1.2Ni0.13Co0.13Mn0.54O2 powder was synthesized by an aqueous solution method, followed by calcination at 900 °C in air, and the surface was then modified by coating with samaria doped ceria (SDC). Both the pristine and the surface modified materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and electrochemical measurements. The SDC coating with 1 wt.% was found to be the most effective in improving the discharge capacity. Specifically, it delivered 261 mAh g-1 at 0.1 C rate with lower initial irreversible capacity loss. This superior electrochemical performance is attributed to the function of SDC as protective layer suppressing the side reaction between the electrode and the electrolyte, and decreasing the electron charge transfer resistance, as evidenced by the collected electrochemical impedance spectroscopy (EIS) data. © 2014 Elsevier Ltd. All rights reserved.


Cui Y.,Harbin Institute of Technology | Chen J.,Harbin Institute of Technology | Huang K.,University of South Carolina | Du C.,Tianjin University | And 3 more authors.
RSC Advances | Year: 2016

Significant efforts have recently been devoted to developing commercially viable high-capacity and low-cost lithium sulfur (Li-S) batteries. In this paper, we report Na-X zeolite templated porous carbon (ZPC) filled with sulfur as a cathode material for Li-S batteries. To immobilize liquid Li sulfide, the surface of NCP was modified by amphiphilic N-polyvinylpyrrolidone (PVP), making ZPC amphiphilic (denoted as A-ZPC). ZPC, A-ZPC and their corresponding composites with sulfur (ZPC-S and A-ZPC-S) were analyzed by various physical characterizations, charge-discharge profiling and electrochemical impedance spectroscopy (EIS). The results showed excellent performance of the A-ZPC-S composite cathode with 46 wt% sulfur loading, a specific capacity can be retained at 691 mA h g-1 even after 300 cycles under a rate of 1C, fading only 0.142% per cycle. © The Royal Society of Chemistry 2016.


Ren L.,Harbin Institute of Technology | Chen J.,Harbin Institute of Technology | Wang X.,Tianjin Polytechnic University | Zhi M.,Zhejiang University | And 2 more authors.
RSC Advances | Year: 2015

Facile synthesis of porous and hollow spinel materials is highly desirable for their extensive applications in energy storage fields. In this work, uniform and decentralized flower-like CoMn2O4 microspheres were synthesized and characterized for supercapacitor electrodes in neutral aqueous electrolyte. In this contribution, uniform microsphere precursors were firstly fabricated by a solvothermal method, followed by a low temperature calcination process for crystallization. A detailed study shows that the deionized (DI) water content plays an important role in the solvothermal process to optimize the morphology of the microspheres. In 1 M Na2SO4, the spinel electrode material has a working potential window as high as 1.1 V and a specific capacitance of 188 F g-1. Besides, the electrode material exhibits excellent cycling stability by retaining 93% of its original capacitance after 1000 cycles. Therefore, the flower-like microspheres of CoMn2O4 spinel are promising candidates for supercapacitor applications. © 2015 The Royal Society of Chemistry.

Loading Dongguan Mcnair Technology Co. collaborators
Loading Dongguan Mcnair Technology Co. collaborators