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Chen Z.,South China Normal University | Huang W.,Guangzhou Tinci Materials Technology Co. | Lu D.,Foshan Polytechnic | Zhao R.,South China Normal University | Chen H.,South China Normal University
Materials Letters | Year: 2013

Zn2V2O7 nanorods were successfully synthesized by a hydrothermal route for the application in the Lithium ion batteries. The effects of the reacting time on the Zn2V 2O7 nanorods as well as the corresponding electrochemical properties were investigated. Results show that the obtained sample under the optimum condition possesses high crystallinity; the width and the thickness are in the range of 40-60 nm and 20-40 nm, respectively. Based on the observations, a possible growth mechanism of Zn2V2O7 nanorods could be described as a reacting-exfoliating-splitting process. Besides, the Zn2V2O7 nanorods used as anode materials in rechargeable lithium-ion battery can exhibit a highly reversible discharge/charge capacity and excellent rate property at a current density as high as 0.1 A g-1. This might be attributed to the intrinsic characteristics of the layered structure of Zn2V2O 7 nanorods. © 2013 Elsevier B.V. Source


Zuo X.,South China Normal University | Wu J.,South China Normal University | Fan C.,South China Normal University | Lai K.,South China Normal University | And 2 more authors.
Electrochimica Acta | Year: 2014

In order to overcome the severe capacity fading of LiMn2O 4/graphite cells cycled at elevated temperature, methylene methanedisulfonate (MMDS) is newly evaluated as an electrolyte additive to improve the thermal stability of LiMn2O4 cathode. The cell using 1.0 mol L-1LiPF6 -EC/EMC/DMC (1:1:1, weight ratio) with 0.5 wt.% MMDS additive keeps 79.2% of initial capacity after100 cycles at 60 °C, whereas it is only 52.7% for the cell without additive. After the storage at 85°C for 24 h, the cell with 0.5 wt.% MMDS additive exhibits higher discharge capacity retention (82.5%) than the cell without additive (71.8%), and the change of thickness, resistance and discharge voltage plateaus decrease. The effects of the additive are characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), transmission electron microscopy (TEM), as well as electrochemical performance tests. These results suggest that MMDS additive can form better electrochemical and thermal stability of surface film on the LiMn2O4 electrode, which reduces both the decomposition of the electrolyte and the dissolution of Mn ion in the electrolyte at elevated temperature, thus leads to the obvious improvement on the thermal stability of LiMn2O4 cathode. © 2014 Elsevier Ltd. Source


Zuo X.,South China Normal University | Fan C.,South China Normal University | Liu J.,Guangzhou Tinci Materials Technology Co. | Xiao X.,South China Normal University | And 2 more authors.
Journal of Power Sources | Year: 2013

This study demonstrates that tris(trimethylsilyl)borate (TMSB) additive in the electrolyte can dramatically improve the cycling performance of LiNi0.5Co0.2Mn0.3O2/graphite cell at higher voltage operation. And the effects of this additive are characterized by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In the voltage range of 3.0-4.4 V, LiNi0.5Co0.2Mn0.3O2/graphite cell with TMSB in the electrolyte retains about 92.3% of its initial capacity compared to the cell without additive in the electrolyte that retains only 28.5% of its initial capacity after 150 cycles, showing the promising prospect of TMSB at higher voltage. The enhanced cycling performance is attributed to the thinner film originated from TMSB on the LiNi0.5Co0.2Mn0.3O2 and the combination of TMSB with PF6 - and F- in the electrolyte, which not only protects the undesirable decomposition of EC solvents but also results in lower interfacial impedance. © 2012 Elsevier B.V. All rights reserved. Source


Zuo X.,South China Normal University | Fan C.,South China Normal University | Xiao X.,South China Normal University | Liu J.,Guangzhou Tinci Materials Technology Co. | Nan J.,South China Normal University
Journal of Power Sources | Year: 2012

In order to overcome the capacity fading of LiCoO 2/graphite Lithium-ion batteries (LIBs) cycled in the voltage range of 3.0-4.5 V (vs. Li/Li +), methylene methanedisulfonate (MMDS) is newly evaluated as an electrolyte additive. The linear sweep voltammetry (LSV) and cyclic voltammetry (CV) indicate that MMDS has a lower oxidation potential in the mixed solvents of ethylene carbonate (EC) and ethyl methyl carbonate (EMC), and participates in the formation process of the cathode electrolyte interface (CEI) film. With the addition of 0.5 wt.% MMDS into the electrolyte, the capacity retention of the LiCoO 2/graphite cells cycled in 3.0-4.5 V is significantly increased from 32.0% to 69.6% after 150 cycles, and the rate capacity is also improved compared with the cells without MMDS additive in the electrolyte, showing the promising prospect in the electrolyte. In addition, the results of electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) demonstrate that the enhanced electrochemical performances of the cells can be ascribed to the modification of components of cathodes surface layer in the presence of MMDS, which resulting the suppression of the electrolyte oxidized decomposition and the improvement of CEI conductivity. © 2012 Elsevier B.V. All rights reserved. Source


Zuo X.,South China Normal University | Fan C.,South China Normal University | Xiao X.,South China Normal University | Liu J.,Guangzhou Tinci Materials Technology Co. | Nan J.,South China Normal University
ECS Electrochemistry Letters | Year: 2012

Methylene methanedisulfonate (MMDS) is evaluated as a new electrolyte additive for improving the cycling performance of the LiNi0.5Co0.2Mn0.3O2/ graphite cells cycled in the voltage range of 3.0-4.4 V.With the addition of 0.5 wt% MMDS in the electrolyte, the capacity retention of the cells increases from 70.7% to 94.1% after 100 cycles in 3.0-4.4 V, but has no difference in 3.0-4.2 V. The enhanced cycling performance of the cells with MMDS additive is ascribed to the surface modification of LiNi0.5Co0.2Mn0.3O2 cathode, which not only improves the conductivity of cathode electrolyte interface film but also suppresses the solvent decomposition at high voltage. © 2012 The Electrochemical Society. Source

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