Zhaoxiang Wang

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Organization: Institute of Physics
Department: Laboratory for Solid State Ionics
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Co-reporter:Xin Feng, Zhenzhong Yang, Daichun Tang, Qingyu Kong, Lin Gu, Zhaoxiang Wang and Liquan Chen  
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 2) pp:1257-1264
Publication Date(Web):05 Nov 2014
DOI:10.1039/C4CP04087B
Li-rich layered Li1+xMnyM1−x−yO2 (or denoted xLi2MnO3·(1 − x)LiMO2, M = Ni, Co, Mn, etc.) are promising cathode materials for high energy-density Li-ion batteries. However, their commercial applications suffer from problems such as a drop in the capacity and discharge voltage during cycling. In this work, the cycling performance of a layered oxide Li1.2Ni0.13Co0.13Mn0.54O2 is improved by integration with spinel LiNi0.5Mn1.5O4 to obtain a layered–spinel composite. Characterization by powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) as well as cyclic voltammetry (CV) indicates that delayed degradation of layered Li2MnO3 and the suppressed growth of LiMn2O4-like spinel are responsible for the performance improvement.
Co-reporter:Xiangpeng Fang, Chunxiu Hua, Xianwei Guo, Yongsheng Hu, Zhaoxiang Wang, Xueping Gao, Feng Wu, Jiazhao Wang, Liquan Chen
Electrochimica Acta 2012 Volume 81() pp:155-160
Publication Date(Web):30 October 2012
DOI:10.1016/j.electacta.2012.07.020
Transition metal sulfides are regarded as another type of high-performance anode materials following the transition metal oxides for lithium ion batteries. However, the lithium storage mechanisms of these sulfides are complicated. This work is intended to evaluate the electrochemical performances of molybdenum disulfide (MoS2) and find out its lithium storage mechanism at different lithium insertion stages. It is found that although the MoS2 shows excellent cycling stability in different voltage ranges, its structural transition is irreversible in the initial cycling. In contrast to the traditional beliefs, metallic Mo is found inert and Li2S/S is the redox couple in a deeply discharged MoS2/Li cell (0.01 V vs. Li/Li+). The metallic Mo nanoparticles are believed to be responsible for the enhanced cycling stability of the cell and act as the electronically conducting phase in the capacitive energy storage on the interfaces or grain boundaries of Mo/Li2Sx nanocomposite. In addition, the Mo/Li2S nanocomposite can be used as a cathode material for lithium–sulfur batteries.
Co-reporter:Ya Mao, Qingyu Kong, Bingkun Guo, Xiangpeng Fang, Xianwei Guo, Lian Shen, Michel Armand, Zhaoxiang Wang and Liquan Chen  
Energy & Environmental Science 2011 vol. 4(Issue 9) pp:3442-3447
Publication Date(Web):24 Jun 2011
DOI:10.1039/C1EE01275D
Current lithium ion battery (LIB) technologies are all based on inorganic electrodes though organic materials have been hyped as electrodes for years. Disadvantages such as low specific capacity and poor rate performance hinder their applications. Here we report a novel high-performance organometallic lithium-storage material, a polypyrrole-iron-oxygen (PPy-Fe-O) coordination complex. Extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations indicate that this complex has a multilayer structure. The strong and stable intralayer Fe–N coordination permits the material to possess high specific capacity, the high reversibility of its interlayer Fe–O–Fe interaction during cycling ensures its high cycling stability and the conducting PPy matrix endows it with outstanding rate performance. These findings pave the way to constructing a new type of high-performance organic anode materials for LIBs.
Co-reporter:Bin Xu, Lu Shi, Xianwei Guo, Lu Peng, Zhaoxiang Wang, Shi Chen, Gaoping Cao, Feng Wu, Yusheng Yang
Electrochimica Acta 2011 Volume 56(Issue 18) pp:6464-6468
Publication Date(Web):15 July 2011
DOI:10.1016/j.electacta.2011.04.130
Mesoporous hard carbon is obtained by pyrolyzing a mixture of sucrose and nanoscaled calcium carbonate (CaCO3) particles. The microstructure of the carbon is characterized by N2 adsorption/desorption, Hg porosimetry, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman spectroscopy. The electrochemical performances of the carbon as an anode material for lithium ion batteries are evaluated by galvanostatic charge/discharge and cyclic voltammetry tests. It is shown that this mesoporous carbon possesses high capacity, good cycling performance and rate capability, indicating the promising application of nano-CaCO3 particle as template in massive fabrication of mesoporous carbon anode materials for lithium ion batteries.Highlights► CaCO3 nano-particle is used as a template of mesoporous carbon. ► Nano-CaCO3 template method is very simple, cheap and easy for mass production. ► The mesoporous carbon is used as anode materials for lithium ion batteries. ► The carbon possesses high capacity, good cycling performance and rate capability.
Co-reporter:Xianwei Guo ; Xiangpeng Fang ; Ya Mao ; Zhaoxiang Wang ; Feng Wu ;Liquan Chen
The Journal of Physical Chemistry C 2011 Volume 115(Issue 9) pp:3803-3808
Publication Date(Web):February 14, 2011
DOI:10.1021/jp111015j
Energy storage was realized on the interfaces between Fe and Li3PO4 nanograins in situ fabricated by discharging commercial LiFePO4 to 0.005 V vs Li+/Li. X-ray diffraction and high-resolution transmission electron microscopy indicate that both the metallic Fe and Li3PO4 nanocrystallites are stable up to 4.2 V. The solid electrolyte interphase layer on the nanocomposite does not decompose until 1.7 V according to infrared spectroscopic analysis. The Fe/Li3PO4 nanocomposite stores up to 220 mAh g−1 of lithium without any electrochemical reactions. This is a purely lithium storage behavior distinct from that on the electrodes of supercapacitors or traditional secondary batteries.
Co-reporter:Dr. Bingkun Guo;Dr. Qingyu Kong;Dr. Ying Zhu;Ya Mao; Zhaoxiang Wang; Meixiang Wan;Liquan Chen
Chemistry - A European Journal 2011 Volume 17( Issue 52) pp:14878-14884
Publication Date(Web):
DOI:10.1002/chem.201002379

Abstract

Current lithium-ion battery (LIB) technologies are all based on inorganic electrode materials, though organic materials have been used as electrodes for years. Disadvantages such as limited thermal stability and low specific capacity hinder their applications. On the other hand, the transition metal oxides that provide high lithium-storage capacity by way of electrochemical conversion reaction suffer from poor cycling stability. Here we report a novel high-performance, organic, lithium-storage material, a polypyrrole–cobalt–oxygen (PPy-Co-O) coordination complex, with high lithium-storage capacity and excellent cycling stability. Extended X-ray absorption fine structure and Raman spectroscopy and other physical and electrochemical characterizations demonstrate that this coordination complex can be electrochemically fabricated by cycling PPy-coated Co3O4 between 0.0 V and 3.0 V versus Li+/Li. Density functional theory (DFT) calculations indicate that each cobalt atom coordinates with two nitrogen atoms within the PPy-Co coordination layer and the layers are connected with oxygen atoms between them. Coordination weakens the CH bonds on PPy and makes the complex a novel lithium-storage material with high capacity and high cycling stability.

Co-reporter:Xianwei Guo, Xia Lu, Xiangpeng Fang, Ya Mao, Zhaoxiang Wang, Liquan Chen, Xiaoxue Xu, Hong Yang, Yinong Liu
Electrochemistry Communications 2010 Volume 12(Issue 6) pp:847-850
Publication Date(Web):June 2010
DOI:10.1016/j.elecom.2010.04.003
Hollow microspheres composed of phase-pure ZnFe2O4 nanoparticles (hierarchically structured) have been prepared by hydrothermal reaction. The unique hollow spherical structure significantly increases the specific capacity and improves capacity retention of this material. The product of each phase transition during initial discharge (ZnFe2O4 ↔ Li0.5ZnFe2O4 ↔ Li2ZnFe2O4 → Li2O + Li–Zn + Fe) and their structural reversibility are recognized by X-ray diffraction and electrochemical characterization. The products of the deeply discharged (Li–Zn alloy and Fe) and recharged materials (Fe2O3) were clarified based on high resolution transmission electron microscopic technique and first-principle calculations.
Co-reporter:Xiangpeng Fang, Xia Lu, Xianwei Guo, Ya Mao, Yong-Sheng Hu, Jiazhao Wang, Zhaoxiang Wang, Feng Wu, Huakun Liu, Liquan Chen
Electrochemistry Communications 2010 Volume 12(Issue 11) pp:1520-1523
Publication Date(Web):November 2010
DOI:10.1016/j.elecom.2010.08.023
Nanorods of MnO2, Mn3O4, Mn2O3 and MnO are synthesized by hydrothermal reactions and subsequent annealing. It is shown that though different oxides experience distinct phase transition processes in the initial discharge, metallic Mn and Li2O are the end products of discharge, while MnO is the end product of recharge for all these oxides between 0.0 and 3.0 V vs. Li+/Li. Of these 4 manganese oxides, MnO is believed the most promising anode material for lithium ion batteries while MnO2 is the most promising cathode material for secondary lithium batteries.
Co-reporter:Shiyu Chen, Zhaoxiang Wang, Hailei Zhao, Hongwei Qiao, Helin Luan, Liquan Chen
Journal of Power Sources 2009 Volume 187(Issue 1) pp:229-232
Publication Date(Web):1 February 2009
DOI:10.1016/j.jpowsour.2008.10.091
Allyl tris(2,2,2-trifluoroethyl) carbonate (ATFEC) was synthesized as a bi-functional additive of flame retardant and film former in electrolytes for lithium ion batteries (LIBs). The flame retardancy of the additive was characterized with differential scanning calorimetry (DSC) and self-extinguishing time (SET). It is shown that adding 1 vol.% ATFEC in 1 M LiPF6/propylene carbonate (PC) can effectively enhance the thermal stability of the electrolyte and suppress the co-intercalation of PC into the graphitic anode. Further evaluation indicates that the additive hardly affect the conductivity of electrolyte. These support the feasibility of using ATFEC as an additive on formulating an electrolyte with multiple functions such as film-forming enhancement, high thermal stability and high ionic conductivity.
Co-reporter:Bingkun Guo, Jie Shu, Kun Tang, Ying Bai, Zhaoxiang Wang, Liquan Chen
Journal of Power Sources 2008 Volume 177(Issue 1) pp:205-210
Publication Date(Web):15 February 2008
DOI:10.1016/j.jpowsour.2007.11.003
Nanoscaled tin (Sn) particles were embedded in the mesopores of hard carbon spherules (HCS) to form a composite anode material for lithium ion batteries. The structure of the obtained composite was characterized by X-ray diffraction (XRD) and the electrochemical performances were evaluated by galvanostatic cycling and cyclic voltammetry. It is found that embedding Sn nanoparticles into HCS not only results in a composite material with high-lithium storage capacity and capacity retention, but also increases the initial coulombic efficiency of the composite. Based on the infrared spectroscopic analysis, the enhanced initial coulombic efficiency is attributed to the nano-tin-induced decomposition of the ROCO2Li species in the solid electrolyte interphase (SEI) layer.
Co-reporter:Ying Bai, Yanfeng Yin, Na Liu, Bingkun Guo, Hongjun Shi, Jianyong Liu, Zhaoxiang Wang, Liquan Chen
Journal of Power Sources 2007 Volume 174(Issue 1) pp:328-334
Publication Date(Web):22 November 2007
DOI:10.1016/j.jpowsour.2007.09.023
As the continuance of our series study on LiCoO2 surface modification, the complicated traditional surface coating method is replaced with simple addition of amorphous YPO4 and Al2O3 in commercial LiCoO2 or in commercial electrolyte based on our understanding to the improvement mechanism of surface modification. Comprehensive studies by X-ray photoelectron spectroscopy (XPS), gas chromatography and mass spectroscopy (GC–MS), inductively coupled plasma (ICP) and Fourier transformed infrared (FTIR) indicate that the products of spontaneous reaction between the additive and the LiPF6 based electrolyte are responsible for the performance improvements.
Co-reporter:Xin Feng, Zhenzhong Yang, Daichun Tang, Qingyu Kong, Lin Gu, Zhaoxiang Wang and Liquan Chen
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 2) pp:NaN1264-1264
Publication Date(Web):2014/11/05
DOI:10.1039/C4CP04087B
Li-rich layered Li1+xMnyM1−x−yO2 (or denoted xLi2MnO3·(1 − x)LiMO2, M = Ni, Co, Mn, etc.) are promising cathode materials for high energy-density Li-ion batteries. However, their commercial applications suffer from problems such as a drop in the capacity and discharge voltage during cycling. In this work, the cycling performance of a layered oxide Li1.2Ni0.13Co0.13Mn0.54O2 is improved by integration with spinel LiNi0.5Mn1.5O4 to obtain a layered–spinel composite. Characterization by powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) as well as cyclic voltammetry (CV) indicates that delayed degradation of layered Li2MnO3 and the suppressed growth of LiMn2O4-like spinel are responsible for the performance improvement.
Sodium titanium oxide
Ferrate(3-),hexakis(cyano-kC)-,iron(3+) (1:1), (OC-6-11)-
MAGNESIUM CITRATE
lithium manganite