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Liu Y.F.,Harbin Institute of Technology | Liu Y.F.,Heilongjiang University | Yuan G.H.,Harbin Institute of Technology | Jiang Z.H.,Harbin Institute of Technology | And 2 more authors.
Journal of Alloys and Compounds | Year: 2014

Ni(OH)2-graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH)2. According to N2adsorption/desorption analysis, the Brunauer-Emmett-Teller surface area of graphene sheet-carbon nanotube composite (109.07 m2g-1) was larger than that of pure graphene sheets (32.06 m2g-1), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH)2nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH)2. The specific capacitance of Ni(OH)2-graphene sheet-carbon nanotube composite was 1170.38 F g-1at a current density of 0.2 A g-1in the 6 mol L-1KOH solution, higher than those provided by pure Ni(OH)2(953.67 Fg-1) and graphene sheets (178.25 F g-1). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g-1), the capacitance of Ni(OH)2-graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH)2. © 2014 Elsevier B.V. All rights reserved.


Pang C.,Sun Yat Sen University | Pang C.,BTR New Energy Materials Inc. | Song H.,Sun Yat Sen University | Li N.,Sun Yat Sen University | Wang C.,Sun Yat Sen University
RSC Advances | Year: 2015

Si with high theoretical capacity has long suffered from its large volume variation and low electrical transport linked to poor cycling stability and rate performance. Here, a facile approach is reported to mass produce nanostructured Si@carbon with a tunable size of silicon nanoparticles. We performed carbon coating of Si nanoparticles by polyacrylonitrile (PAN) emulsifying and then carbonization. The hollow Si@C nanostructure was obtained via direct etching of Si nanoparticles with HF solution which is more advanced and has better controllability. When evaluated as an anode material for lithium-ion batteries, the C-Si nanocomposites exhibit excellent reversibility and cycling performance. A high capacity of 700 mA h g-1 can be retained after 100 cycles at current densities of 250 mA g-1. The rate capability of the C-Si microfibers is also improved. The special structure is believed to offer better structural stability upon prolonged cycling and to improve the conductivity of the material. This simple strategy could also be applied to prepare other carbon coatings of hollow energy materials. © The Royal Society of Chemistry 2015.


Ren J.-G.,BTR New Energy Materials Inc.
32nd Annual International Battery Seminar and Exhibit | Year: 2015

BTR has dominated the global graphite anode materials market and will continue to expand the business towards other new energy and new materials. SiO is a promising anode material alternative to graphite due to its intrinsic properties of high energy density, low expansion and long cycle life. Carbon-coated SiO by pitch or by CVD has the capacity and efficiency of >1600 mAh/g and 77.0%, respectively. For SiO-contained pouch cell, the energy density can reach ∼700 Wh/L and the capacity retention can reach 86.5% @ 300 cycles; The cylindrical cells comprising SiO work very well for high energy (3.4 Ah) and high power (10C) applications. The current industrial situation of SiO raw materials cannot meet the requirement of SiO anode materials with respect to production capacity, quality control and R&D capability. BTR has achieved the technology innovation of SiO raw materials synthesis and reached the production capacity of 100t/m now.


Yang Y.,City University of Hong Kong | Ren J.-G.,City University of Hong Kong | Ren J.-G.,BTR New Energy Materials Inc. | Wang X.,City University of Hong Kong | And 4 more authors.
Nanoscale | Year: 2013

Anode materials play a key role in the performance, in particular the capacity and lifetime, of lithium ion batteries (LIBs). Silicon has been demonstrated to be a promising anode material due to its high specific capacity, but pulverization during cycling and formation of an unstable solid-electrolyte interphase limit its cycle life. Herein, we show that anodes consisting of an active silicon nanowire (Si NW), which is surrounded by a uniform graphene shell and comprises silicon carbide nanocrystals, are capable of serving over 500 cycles in half cells at a high lithium storage capacity of 1650 mA h g -1. In the anodes, the graphene shell provides a highly-conductive path and prevents direct exposure of Si NWs to electrolytes while the SiC nanocrystals may act as a rigid backbone to retain the integrity of the Si NW in its great deformation process caused by repetitive charging-discharging reactions, resulting in a stable cyclability. © 2013 The Royal Society of Chemistry.


Ni J.,Soochow University of China | Huang Y.,BTR New Energy Materials Inc. | Gao L.,Soochow University of China
Journal of Power Sources | Year: 2013

A hard carbon (HC) prepared from phenolic resins is investigated as a potential electrode material for power Li-ion batteries and hybrid supercapacitors. The electrochemical test results indicate that the HC is capable of delivering a capacity of 526 mAh g -1 (about 40% greater than graphite) with an initial coulombic efficiency of 80%. The constructed Li(Ni 1/3Co 1/3Mn 1/3)O 2/HC full cells shows superior power capabilities, retaining 90% of reversible capacity at a discharge rate as high as 30 C. That is equivalent to a specific energy of 98 Wh kg -1 at a power of 3000 W kg -1. When combined with an activated carbon (AC), the constructed AC/HC hybrid capacitor exhibits a specific capacitance of 21.5 F g -1 or energy density of 22.6 Wh kg -1 (considering the weight of all components of the full cell) at a current of 100 mA g -1. At a power of 480 W kg -1, it delivers an energy density of 20.8 Wh kg -1, which is twice that of a conventional AC/AC supercapacitor. The feature of high energy and power capabilities makes HC materials promising candidates as electrodes for energy storage and conversion application. © 2012 Elsevier B.V. All rights reserved.


The present invention relates to a silicon monoxide composite negative electrode material, which comprises silicon monoxide substrate. Nano-Silicon material uniformly deposited on the silicon monoxide substrate and nanoscale conductive material coating layer on the surface of the silicon monoxide/Nano-Silicon. The preparation method of the silicon monoxide composite negative electrode material includes Nano-Silicon chemistry vapour deposition, nanoscale conductive material coating modification, screening and demagnetizing. The silicon monoxide composite negative electrode material has properties of high specific capacity (>1600 mAh/g), high charge-discharge efficiency of the first cycle (>80%) and high conductivity.


Patent
BTR New Energy Materials Inc. | Date: 2014-04-02

A lithium ion battery graphite negative electrode material and preparation method thereof. The lithium ion battery graphite negative electrode material is a composite material including graphite substrates, surface coating layers coated on the graphite substrates and carbon nanotubes and/or carbon nanofibers grown in situ on the surface of the surface coating layers. The preparation method thereof includes, in solid phase or liquid phase circumstance, the coated carbon material precursor forms the surface coating layer of amorphous carbon by carbonization, and then carbon nanotubes and/or carbon nanofibers having high conductive performance are formed on the surface of the surface coating layers by vapor deposition. This coating mode of the combination of solid phase with gas phase or of liquid phase and gas phase makes the amorphous carbon formed on the surface of the graphite substrates more uniform and dense. The lithium ion battery graphite negative electrode material has properties of high charging-discharging efficiency at first time and excellent cycle stability at either high or low temperatures. The charging-discharging efficiency at first time is up to more than 95%, and the capacity retention after 528 cycles is more than 92%.


Patent
BTR New Energy Materials Inc. | Date: 2014-05-19

The present invention discloses a method for modification of a lithium ion battery positive electrode material. The method comprises the following steps: (1) mixing organic acid and alcohol to obtain an organic solution; (2) adding positive electrode material into the organic solution to obtain a suspension; (3) washing with alcohol solvent after centrifugal separation; (4) drying treatment; the positive electrode material is a nickel-based metal oxide positive electrode material LiNi_(x)M_(1x)O_(2), wherein 0.5x<1 and M is one or two selected from the group consisting of Co, Mn, Al, Cr, Mg, Cu, Ti, Mg, Zn, Zr and V. Compared with the prior art, the method of the present invention utilizes the mixed solution of alcohol and organic acid to wash the positive electrode material thereby soluble Li salt impurities on the surface of the positive electrode material are removed and pH value of the material are significantly decreased; meanwhile, low-temperature drying treatment makes the washed material to be coated with alcohol molecules which can block air molecules, thereby the binding of water molecules and the positive electrode material are avoided and pole piece gumming are prevented, obviously improving high-temperature storage performance and cycling stability of battery. Further, the mixed solution of the alcohol and the organic acid after washing can be recycled, therefore cost is low and pollution on environment is avoided.


The present invention relates to a cathode material of Lithium-Nickel-Cobalt-Aluminum composite oxide, a method of fabricating the same, and a lithium ion battery including the same. The composite cathode material has a core-shell structure, wherein the core portion is made of LiNi_(1-x-y)Co_(x)Al_(y)O_(2 )which is washed with an alcohol and organic acid-mixed solution, wherein 0


The present invention relates to a nano-silicon composite negative electrode material, including graphite matrix and nano-silicon material homogeneously deposited inside the graphite matrix, wherein the nano-silicon composite negative electrode material is prepared by using silicon source to chemical-vapor deposit nano-silicon particles inside hollowed graphite. The nano-silicon composite negative electrode material of the present invention has features of high specific capacity (higher than 1000 mAh/g), high initial charge-discharge efficiency (higher than 93%) and high conductivity. The preparation process of the present invention is easy to operate and control, and has low production cost and is suitable for industrial production.

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