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1.
通过简单浸泡的方法在铜基底上制备出了具有微纳米复合结构的氧化铜,再利用混合硫醇溶液[含HS(CH2)9CH3和 HS(CH2)11OH]对浸泡后的表面进行修饰,通过控制溶液中HS(CH2)11OH的浓度,制备出一系列具有不同浸润性的铜表面,实现表面从超疏水到超亲水的有效调控. 研究发现,表面浸润的可控性源于表面复合结构与不同化学组成的协同作用,微纳米复合结构的存在为表面浸润性的调节提供了必要的条件. 相似文献
2.
气相色谱/质谱测定皮革及其制品中乙二醇醚类有机溶剂的残留量 总被引:1,自引:0,他引:1
建立了同时测定皮革及其制品中12种乙二醇醚类有机溶剂残留量的气相色谱/质谱-选择离子监测方法。以乙酸乙酯为萃取溶剂,在45℃下超声萃取皮革及其制品中的乙二醇醚类有机溶剂,萃取液经固相萃取柱净化后进行气相色谱/质谱-选择离子监测法测定,外标法定量。在信噪比(S/N)=3的条件下,乙二醇单乙醚(EGEE)的检出限为0.10 mg/kg,其余11种乙二醇醚类有机溶剂的检出限均小于0.05 mg/kg。在3个加标水平下,该方法的平均加标回收率为81.2%~95.5%,相对标准偏差(RSD)为1.4%~6.6%(n=9)。该方法简便快捷,灵敏度高,检出限远远低于欧盟法规《化学品的注册、评估、授权和限制》(REACH)的限量要求,适用于皮革及其制品中乙二醇醚类有机溶剂残留量的测定,为制定相关检测标准提供了参考。 相似文献
3.
Honeycomb porous La0.6Sr0.4Co0.2Fe0.8O3−δ-Gd0.2Ce0.8O2−δ (LSCF-GDC) composite cathodes are prepared using the breath figures (BFs) method with nontoxic and easily available water droplets as templates. The fabrication of honeycomb porous membranes is realized in a relatively humid environment, using a volatile solvent. The microstructure and morphology of the membranes produced are investigated by scanning electron microscopy (SEM). The SEM micrographs suggest that experimental conditions, such as ambient temperature, relative humidity, and concentration of polymer and LSCF-GDC powder, which have direct influence on the solvent evaporation affects the pore structure of the porous membranes. Electrochemical impedance spectroscopy (EIS) is used to evaluate the polarization resistance of LSCF-GDC composite cathodes prepared at different experimental conditions. The honeycomb porous LSCF-GDC composite cathode showing average pore diameter of 10 μm illustrates the lowest polarization resistance. 相似文献
4.
5.
Tongyong Yang Kening Sun Zhengyu Lei Naiqing Zhang Ye Lang 《Journal of Solid State Electrochemistry》2011,15(2):391-397
LiNi0.5Mn1.5O4 cathode materials were successfully prepared by sol–gel method with two different Li sources. The effect of both lithium
acetate and lithium hydroxide on physical and electrochemical performances of LiNi0.5Mn1.5O4 was investigated by scanning electron microscopy, Fourier transform infrared, X-ray diffraction, and electrochemical method.
The structure of both samples is confirmed as typical cubic spinel with Fd3m space group, whichever lithium salt is adopted. The grain size of LiNi0.5Mn1.5O4 powder and its electrochemical behaviors are strongly affected by Li sources. For the samples prepared with lithium acetate,
more spinel nucleation should form during the precalcination process, which was stimulated by the heat released from the combustion
of extra organic acetate group. Therefore, the particle size of the obtained powder presents smaller average and wider distribution,
which facilitates the initial discharge capacity and deteriorates the cycling performance. More seriously, there exists cation
replacement of Li sites by transition metal elements, which causes channel block for Li ion transference and deteriorates
the rate capability. The compound obtained with lithium hydroxide exhibits better electrochemical responses in terms of both
cycling and rate properties due to higher crystallinity, moderate particle size, narrow size distribution and lower transition
cation substitute content. 相似文献
6.
Lishuang Fan Yu Zhang Zhikun Guo Bing Sun Da Tian Yujie Feng Naiqing Zhang Kening Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(42):9314-9318
Flexible asymmetric supercapacitors are more appealing in flexible electronics because of high power density, wide cell voltage, and higher energy density than symmetric supercapacitors in aqueous electrolyte. In virtues of excellent conductivity, rich porous structure and interconnected honeycomb structure, three dimensional graphene aerogels show great potential as electrode in asymmetric supercapacitors. However, graphene aerogels are rarely used in flexible asymmetric supercapacitors because of easily re-stacking of graphene sheets, resulting in low electrochemical activity. Herein, flower-like hierarchical Mn3O4 and carbon nanohorns are incorporated into three dimensional graphene aerogels to restrain the stack of graphene sheets, and are applied as the positive and negative electrode for asymmetric supercapacitors devices, respectively. Besides, a strong chemical coupling between Mn3O4 and graphene via the C-O-Mn linkage is constructed and can provide a good electron-transport pathway during cycles. Consequently, the asymmetric supercapacitor device shows high rate cycle stability (87.8 % after 5000 cycles) and achieves a high energy density of 17.4 μWh cm−2 with power density of 14.1 mW cm−2 (156.7 mW cm−3) at 1.4 V. 相似文献
7.
Lifeng Wang Naiqing Ren Dr. Yu Yao Dr. Hai Yang Dr. Wei Jiang Zixu He Dr. Yang Jiang Prof. Shuhong Jiao Prof. Li Song Prof. Xiaojun Wu Prof. Zhong-Shuai Wu Prof. Yan Yu 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214372
Metallic Na is a promising metal anode for large-scale energy storage. Nevertheless, unstable solid electrolyte interphase (SEI) and uncontrollable Na dendrite growth lead to disastrous short circuit and poor cycle life. Through phase field and ab initio molecular dynamics simulation, we first predict that the sodium bromide (NaBr) with the lowest Na ion diffusion energy barrier among sodium halogen compounds (NaX, X=F, Cl, Br, I) is the ideal SEI composition to induce the spherical Na deposition for suppressing dendrite growth. Then, 1,2-dibromobenzene (1,2-DBB) additive is introduced into the common fluoroethylene carbonate-based carbonate electrolyte (the corresponding SEI has high mechanical stability) to construct a desirable NaBr-rich stable SEI layer. When the Na||Na3V2(PO4)3 cell utilizes the electrolyte with 1,2-DBB additive, an extraordinary capacity retention of 94 % is achieved after 2000 cycles at a high rate of 10 C. This study provides a design philosophy for dendrite-free Na metal anode and can be expanded to other metal anodes. 相似文献
8.
Xiaodong Zhu Xinbing Chen Yixing Yuan Kening Sun Naiqing Zhang 《Journal of Solid State Electrochemistry》2012,16(1):313-319
SrCo0.8Fe0.2O3-δ (SCF), as a promising cathode material for intermediate temperature solid oxide fuel cells, possesses a high catalytic activity
for the reduction of O2 to 2O2−. The SCF powder was successfully synthesized by the solid state reaction method and Pechini method and characterized using
XRD, particle analysis, and electrochemical performance measurements. Smaller-particle-size SCF materials (SCF-P) with single
phase are obtained at lower synthesis temperature by the Pechini method and possess better electrochemical performance as
compared with those prepared by the solid state reaction method. The reason is that the Pechini method involves the mixing
of elements at atomic level, so pure SCF phase formation can be accelerated and showed high electrocatalytic activity. The
preparation procedure of SCF cathode was firstly investigated using electrochemical impedance spectroscopy. Results show that
the total polarization resistance and the low-frequency resistance decrease gradually with the reduction of the calcination
temperature for the SCF cathodes. The SCF-P cathode sintered at 1,000 °C possesses the highest porosity and the best electrochemical
performance. It is the result of a comprehensive function of three-phase boundary length, porosity of cathode, and the adhesion
between cathode and electrolyte. The charge-transfer process, together with the adsorption, dissociation, and diffusion of
oxygen, has a strong influence on the whole reaction process of the cathode. The influence of binder amounts on the performance
of the SCF-P cathodes was also studied. 相似文献
9.
Ling Liu Kening Sun Naiqing Zhang Tongyong Yang 《Journal of Solid State Electrochemistry》2009,13(9):1381-1386
To improve the electrochemical properties of Li[Ni1/3Co1/3Mn1/3]O2 at high charge end voltage (4.6 V), a series of the mixed transition metal compounds, Li(Ni1/3Co1/3 − x
Mn1/3M
x
)O2 (M = Mg, Cr, Al; x = 0.05), were synthesized via hydroxide coprecipitation method. The effects of doping Mg, Cr, and Al on the structure and
the electrochemical performances of Li[Ni1/3Co1/3Mn1/3]O2 were compared by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge–discharge tests,
and electrochemical impedance spectroscopy. The XRD results show that all the samples keep layered structures with R3m space group as the Li[Ni1/3Co1/3Mn1/3]O2. SEM images show that all the compounds have spherical shapes and the Cr-doped sample has the largest particle size. Furthermore,
galvanostatic charge–discharge tests confirm that the Cr-doped electrode shows improved cycling performance than the undoped
material. The capacity retention of Li(Ni1/3Co1/3 − 0.05Mn1/3Cr0.05)O2 is 97% during 50 cycles at 2.8∼4.6 V. The improved cycling performance at high voltage can be attributed to the larger particle
size and the prevention of charge transfer resistance (R
ct) increase during cycling. 相似文献
10.
通过简单浸泡的方法在铜基底上制备出了具有微纳米复合结构的氧化铜, 再利用混合硫醇溶液[含HS(CH2)9CH3和 HS(CH2)11OH]对浸泡后的表面进行修饰, 通过控制溶液中HS(CH2)11OH的浓度, 制备出一系列具有不同浸润性的铜表面, 实现表面从超疏水到超亲水的有效调控. 研究发现, 表面浸润的可控性源于表面复合结构与不同化学组成的协同作用, 微纳米复合结构的存在为表面浸润性的调节提供了必要的条件. 相似文献