CERAMICS INTERNATIONAL
·
2012
·Vol. 39
·期 5
·5379-5385
·
IF 1.751
Jingjing Zhou,Jiefeng Zhou,Yuanhao Tang,Yujing Bi,Chenyun Wang,Deyu Wang,Siqi Shi
Using NaF as the only Na precursor, fluorophosphate Na 2 FePO 4 F/C materials have been synthesized via the solid-state reaction. Na 2 FePO 4 F starts to form at 300 °C, becomes the sole crystalline form between 400 and 600 °C, and decomposes at 650 °C. Comparing with the theoretical capacity of 124 mAh g −1 , the sample prepared at 600 °C delivered a discharge capacity of 118 mAh g −1 . The outstanding electrochemical performance is believed to result from the good crystallization and high purity of the synthesized materials . The capacity retentions at 0.5 C and 2 C are 95.8% and 89.8%, respectively, of that at 0.05 C. Furthermore, a discharge capacity of 122 mAh g −1 is maintained under the cycling between 2.0 and 5.2 V vs. Li/Li + , indicating that the second Na + is not extracted from the Na 2 FePO 4 F lattice.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固体化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Xingliang Chen,Yan Wang,Hailing Liu,Shu Jin,Guanglei Wu
The applications of cobalt ferrite and nickel ferrite composite materials on electromagnetic (EM) wave absorption are the research hotspot currently. However, the systematical comparison study between these two ferrites composites have rarely been carried out. Thus, the EM wave absorption performance of interconnected carbon@Ni x Co 1-x Fe 2 O 4 composites with core–shell structures were investigated comprehensively in this work. A series of magnetic nanospheres including NiFe 2 O 4 , cobalt-doped nickel ferrite, nickel–cobalt ferrite, nickel-doped cobalt ferrite and CoFe 2 O 4 were synthesized firstly, and then uniformly encapsulation by carbon rendered the corresponding C@Ni x Co 1-x Fe 2 O 4 composites nanospheres. Synthesis reactions involved for C@Ni x Co 1-x Fe 2 O 4 formation were investigated in detail, and afterwards their magnetic behavior, EM wave absorption performance and absorbing mechanism were thoroughly explored and analyzed. Results show that when nickel is dominant element and cobalt is doping element (Ni 0.75 Co 0.25 Fe 2 O 4 ), the composite nanosphere exhibits optimum EM wave absorption performance. When the sample thickness is just 1.9 mm, its RL min value can reach −51 dB, and the corresponding EAB width is 3.3 GHz. The synthesized C@Ni 0.75 Co 0.25 Fe 2 O 4 can be qualified as an efficient and thin electromagnetic wave absorber, which is mainly attributed to its special structure, fair electromagnetic matching and impedance matching.
研究领域:
材料科学
·
电磁学
·
纳米材料
·
功能材料
·
复合材料工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Mengyi Wang,Li Yin,Mingqi Li,Shaohua Luo,Chao Wang
To develop low-cost, high-capacity and long-life anode materials for lithium-ion batteries, glucose-C and F-doped C coated SiO composites with adjustable pore structure (p-SiO@gl-C@F-doped C) are synthesized by facile and scalable methods. The combination of the heterogeneous dual-carbon shells and porous structure significantly promotes the reaction kinetics of the electrode, effectively suppresses and buffers the volume expansion of SiO, and largely enhances the stability of solid electrolyte interface of the electrode. In a half cell, the optimized p-SiO@gl-C@F-doped C (7:3) composite shows a stable discharge capacity of 785 mAh g −1 at a current density of 200 mA g −1 . The discharge capacity is maintained at 772 mAh g −1 after 200 cycles. At a current density of 400 mA g −1 , the electrode shows a discharge capacity of 633 mAh g −1 after 500 cycles, with a capacity degradation of ∼0.0096% per cycle from the 2nd cycle to the 500th cycle. The full cell which is composed of the commercial LiFePO 4 as a cathode and the optimized composite as an anode, exhibits high capacity and good cycling stability.
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米复合材料
·
电池技术
✓ 已验证
DOI
高影响因子
IONICS
·
2016
·Vol. 22
·期 8
·1343-1351
·
IF 2.119
Li Qi-Ling,Xu Wang-Qiong,Bai Hong-Li,Guo Jun-Ming,Su Chang-Wei
ZnO-coated LiMn 2 O 4 cathode materials were prepared by a combustion method using glucose as fuel. The phase structures, size of particles, morphology, and electrochemical performance of pristine and ZnO-coated LiMn 2 O 4 powders are studied in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge test, and X-ray photoelectron spectroscopy (XPS). XRD patterns indicated that surface-modified ZnO have no obvious effect on the bulk structure of the LiMn 2 O 4 . TEM and XPS proved ZnO formation on the surface of the LiMn 2 O 4 particles. Galvanostatic charge/discharge test and rate performance showed that the ZnO coating could improve the capacity and cycling performance of LiMn 2 O 4 . The 2 wt% ZnO-coated LiMn 2 O 4 sample exhibited an initial discharge capacity of 112.8 mAh g −1 with a capacity retention of 84.1 % after 500 cycles at 0.5 C. Besides, a good rate capability at different current densities from 0.5 to 5.0 C can be acquired. CV and EIS measurements showed that the ZnO coating effectively reduced the impacts of polarization and charge transfer resistance upon cycling.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
纳米材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2009
·
IF 1.51
Rongguan Lv,Jun Yang,Pengfei Gao,Yanna NuLi,Jiulin Wang
A mixture of nanoporous and nanofibrous silicon (NPNF-Si) is prepared by the mechanochemical reduction of SiCl 4 using Li 13 Si 4 as reducing agent in the presence of Super P carbon (SP) and the following thermal treatment and washing process. Morphologies and structures of the as-obtained composites are investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). After carbon coating via pyrolysis of polyvinyl chloride (PVC), the resulting NPNF-Si/SP/C composite is evaluated for the use as anode material in lithium-ion battery. It exhibits the first discharge capacity of 746.6 mAh g −1 at current density of 0.2 mA mg −1 and capacity retention of 91.1% after 30 cycles. The good electrochemical performance arises from the particular Si nano-structure, which can alleviate the volume effect during lithium insertion and extraction.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
锂离子电池
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·Vol. 43
·期 12
·9327-9333
·
IF 2.986
Nan Zhou,Shengxiong Huang,Tao Hong,Wei Luo,Yun Tian,Xiangyang Lu,Zhi Zhou
In this paper, LiTi 2 (PO 4 ) 3 @carbon composite as anode for aqueous lithium ion battery has been successfully synthesized by in-situ carbon coating method using oxalic acid and glucose as double carbon sources. XRD results confirm the rhombohedral NASICON-type LiTi 2 (PO 4 ) 3 structure of the as-prepared composite. The LiTi 2 (PO 4 ) 3 @carbon composite using double carbon sources (LTP-OG-10) disperses well, and the coated carbon layer has the appropriate thickness of 3–7 nm, which result in proper balance of the good electrical conductivity and the fast kinetics of diffusion of lithium ions . LTP-OG-10 exhibits better electrochemical performance compared with those using oxalic acid (LTP-O) or glucose (LTP-G) single carbon source. LTP-OG-10 anode delivers the discharge capacity of 112.5 mA h g −1 , 96.8 mA h g −1 , and 54.2 mA h g −1 at 0.2 C, 5 C and 20 C, respectively, much larger than that of LTP-O and LTP-G. Moreover, LTP-OG-10 demonstrated excellent cycling performance, with the capacity retention of 71.1% after 400 cycles at 0.2 C, 22.9% higher than that of LTP-G. The good electrochemical properties of LTP-OG-10 is mainly ascribed to the increase of defects, high-quality and appropriate thickness of carbon layer. Our study reveals that preparing LiTi 2 (PO 4 ) 3 @carbon composite using double carbon sources is an efficient approach to enhance its electrochemical properties.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机非金属材料
·
功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Zhixin Yao,Yuandong Peng,Chao Xia,Xuwu Yi,Shenghua Mao,Miantuan Zhang
The effect of calcination temperature on the coating layer and the phase of the alloy matrix is the main problem to improve the heat treatment process of SMCs and obtain excellent magnetic properties . In this study, FeNiMo@Al 2 O 3 powders which were coated by sol-gel and calcined at 900–1300 °C were prepared and these powders were pressed into SMCs. The results showed that the surface of the powder was uniformly coated with Al 2 O 3 . As the heat treatment temperature increases, the phase of the coating changed from AlOOH to γ-Al 2 O 3 , δ-Al 2 O 3 , θ-Al 2 O 3 , and α-Al 2 O 3 . Meanwhile, the new phase γ-Fe, Ni appeared in the alloy matrix. The magnetic permeability of the sample is very stable in the frequency range of 10–500 kHz. The magnetic loss decreases first and then increases, with a minimum at 1100 °C. The permeability and magnetic loss of the sample pressed from the powder obtained by calcination at 1100 °C are 321.78 mw/cm 3 and 87.61 (50 kHz, 100 mT) at the typical industrial application conditions of Iron–Nickel SMCs. The microstructure and the magnetic properties show that the obtained α-Al 2 O 3 have excellent insulation and heat resistance. This resulted in a significant reduction in core losses of FeNiMo SMCs.
研究领域:
材料科学
·
磁性材料
·
无机非金属材料
·
粉末冶金
·
功能材料
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
K. Huang,K. Bi,J.C. Xu,C. Liang,S. Lin,W.J. Wang,T.Z. Yang,Y.X. Du,R. Zhang,H.J. Yang,D.Y. Fan,Y.G. Wang,M. Lei
Novel nanocomposites of spherical graphite-carbon encased tungsten carbide (GC-WC) are synthesized by solid state reaction with melamine and WO 3 as precursors under N 2 atmosphere. The diameters of the GC-WC composites range from 50 to 200 nm and the WC nanoparticles inside with an average size of ca. 15 nm distribute uniformly. The characterization results indicate that the GC-WC is composed of few layers of graphite carbon and WC nanoparticles with high crystallization and purity. Moreover, the electrocatalytic performance of GC-WC for the oxygen reduction reaction (ORR) in alkaline medium is further investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with or without 3 M methanol. The results show that GC-WC has a considerable performance for ORR in the view of activity, stability and methanol tolerance, which may further used as proper supports for noble-metal based ORR catalysts in alkaline fuel cell . The synergetic interaction between the carbide nanoparticles and graphite carbon, which means that the surface graphite carbon layers are activated by WC nanoparticles for ORR and in turn protect inner WC from highly oxidizing environments has also been verified.
研究领域:
材料科学
·
纳米科技
·
电化学
·
能源材料
·
催化化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Hedong Chen,Shaofeng Wang,Xiaojing Liu,Xianhua Hou,Fuming Chen,Hui Pan,Haiqing Qin,Kwok-ho Lam,Yingchun Xia,Guofu Zhou
The double-coated Si-based composite (nano-Si@carbon@void@graphene sheets) with the excellent electrochemical properties have been successfully designed and prepared via a spray drying method. The composite electrode at 0.1 A g −1 presents a high initial discharge/charge capacity of 2744.9/2389.8 mAh g −1 , representing high initial coloumbic efficiency of 87.1%. After 200 cycles, a high charge capacity of 1325.2 mAh g −1 is obtained. Even at 0.8 A g −1 and 1.6 A g −1 , the composite electrode still maintain high capacities of 1466.1 mAh g −1 and 561.5 mAh g −1 , respectively. The enhanced performance is mainly attributed to the double-coated structure with void space resulting from the carbon layer and wrinkled graphene sheets . The three-dimensional network structure from carbon shell and graphene is capable of improving the electrical conductivity of the composite, buffering the significant volume expansion due to the intercalation and deintercalation of lithium-ions on the Si-based electrode, providing accommodation space for the volume changes and diffusion paths for lithium-ions. Furthermore, the part amorphous structure derived from the nano-silicon exhibits a cushioning effect on the electrode structure during the discharge/charge process of lithium-ion batteries.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
功能材料
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 44
·17502-17510
·
IF 3.069
Jie Ren,Zhenguo Wang,Yu Feng,Bangjun Guo,Ke Yu,Ziqiang Zhu
In this work, we report the first-principles investigation and synthesis method for a hollow-MoS2/C heterostructure applied to a hydrogen evolution catalytic material. First principles investigation was used to calculate the free energy of hydrogen ion adsorption at the heterostructure interface at different surface adsorption ratios. The change of the density of states before and after carbon coating proved that carbon coating improves the conductivity of the catalyst. Higher reactivity areas and higher conductivity can significantly improve hydrogen evolution catalytic performance, which is also demonstrated by electrochemical testing. Hollow-MoS2/C exhibits a low onset overpotential of 96 mV and a low Tafel slope of 67.4 mV dec−1, as well as good catalytic stability. The composite catalyst prepared by a two-step method has a larger specific surface area and a larger porosity, can significantly suppress the collapse and stacking effect caused by the electrode circulation process, and improve the cyclic reversibility and stability of the material. This work is expected to provide a meaningful reference for solving the problem of cycling performance degradation of non-precious metal-catalyzed hydrogen evolution materials.
研究领域:
材料化学
·
电化学
·
纳米材料科学
·
催化化学
·
能源材料
·
理论计算化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Na Zhang,Yu Liu,Jianhua Yang,Shuming Zhang,Shiyang He
The Si-TiO 2 based composites with a nanosized multi-sphere structure have been developed as novel anode for lithium ion cells . The Si spheres are highly embedded within the titanium dioxide nanoparticles via a hydrothermal synthesis route. The as-proposed sphere-stack like morphology achieves a superior cycling stability for lithium storage. The existence of TiO 2 is in favor for the mechanical stability of Si during charge-discharge and conversely reduces the obtained capacity of the composite. Furthermore, the Si/TiO 2 composite is coated by pyrolysized carbon. The reversible discharge capacity of the Si/TiO 2 /C composite reaches to 976 mAh g −1 after 50 cycles. Carbon coating is beneficial for the rate capability of the Si/TiO 2 based composite.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
无机非金属材料
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Hedong Chen,Zhoulu Wang,Xianhua Hou,Lijun Fu,Shaofeng Wang,Xiaoqiao Hu,Haiqing Qin,Yuping Wu,Qiang Ru,Xiang Liu,Shejun Hu
Carbon-coated core-shell structure artificial graphite@plasma nano-silicon@carbon (AG@PNSi@C) composite, applying as lithium ion battery anode material , has been prepared via spray drying method. The plasma nano-silicon (<100 nm), which contained amorphous silicon , was synthesized by radio frequency induction plasma system with the high temperatures processing capability and high quench rates. The artificial graphite in the composite acts as the core which supports the particle and provides electroconductivity , while PNSi attached on the surface of the core, enhances the specific capacity of the composite. The as prepared composite shows superior performance as anode in lithium-ion batteries, regarding to the initial Coulombic efficiency and cycle life. The initial Coulombic efficiency of AG@PNSi@C electrode is 81.0% with a discharge capacity of 553 mAh g −1 and a recharge capacity of 448 mAh g −1 . During cycling, AG@PNSi@C exhibits excellent performance with a very low capacity fading that the discharge capacity maintains 498.2 mAh g −1 and 449.4 mAh g −1 after 250 cycles and 500 cycles. AG@PNSi@C also shows enhanced resistance against high current density . Besides the remarkable electrochemical performances , the facile and mass-producible synthesis process makes the AG@PNSi@C composite very promising for its application in lithium-ion batteries.
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）