电场辅助制备多壁碳纳米管/聚苯乙烯复合膜的气体分离性能

采用溶液浇铸法制备了不同含量多壁碳纳米管（MWCNTs）和聚苯乙烯（PS）掺杂的气体分离复合膜,成膜过程中在垂直于铸膜液平面的方向上施加场强为2000 V·cm^-1,频率为1 Hz的交变电场,直至溶剂挥发完全。采用荧光分光光度计、体式显微镜和数字万用表考察了膜的荧光特性,铸膜液中MWCNTs对水平电场的响应,MWCNTs在膜中的分散情况以及膜的垂直向电阻率,测定了复合膜对CO₂、CH₄的渗透系数。结果表明电场作用不仅可以实现MWCNTs在膜中的定向排布,还能够使MWCNTs在膜中分散得更均匀,定向复合膜CO₂和CH₄的透过性和选择性都优于非定向复合膜。     

压缩和回复下PA6/MWCNTs/SSFs复合材料导电性研究

通过熔融共混、注射成型将多壁碳纳米管(MWCNTs)和不锈钢纤维(SSFs)与尼龙(PA)6复合制成PA6/MWCNTs/SSFs导电复合材料,在万能试验机上对其进行单轴压缩蠕变和阶梯回复实验,对材料的电阻率、应力、应变进行同步测量,研究不同应力及SSFs含量下复合材料的电阻率变化。结果表明,该复合材料在阶梯应力加载瞬间发生普弹形变,维持恒定应力后,发生高弹形变和粘流形变,阶梯应力卸载后,应变会有所回复。压缩蠕变状态下,当应力为10,20 MPa时,加载瞬间复合材料电阻率会发生突变下降;当应力维持在10 MPa时,电阻率随应变的增加呈下降趋势,即发生电阻蠕变现象,SSFs质量分数为10%的复合材料电阻蠕变现象最为明显;随着应力水平增大,电阻蠕变现象消失,电阻率趋于稳定,但当SSFs质量分数为8%时,电阻率存在较大波动;阶梯回复状态下,复合材料电阻率基本稳定,但当应力卸载到10 MPa时,电阻率存在波动,随着SSFs含量增加,波动趋于平缓。根据Burgers蠕变模型以及聚合物荷载响应特点,认为这主要是由于聚合物分子链的运动对导电通路的影响引起的。     

Modified Carbon Anode by MWCNTs/PANI Used in Marine Sediment Microbial Fuel Cell and its Electrochemical Performance

Improving the performance of anode is a crucial step for increasing power output of marine sediment microbial fuel cells (SMFCs). A multi‐walled carbon nanotube/polyaniline (MWCNTs/PANI) modified anode was prepared by the way of electrochemical deposition and its electrochemical performance is investigated in this paper. Result shows that the wettability of carbon felt becomes better and the number of bacteria (9.52 × 10¹² m⁻²) on anode biofilm is increased respectively, which is 9 times higher than that of the unmodified. The anti‐polarization ability of the modified anode increases significantly and its kinetic activity of electron transfer increases 4 times. Its exchange current density is 3.62 × 10⁻⁵ A cm⁻². The maximum power density of the modified SMFC reaches 527.0 mW m⁻², which is 4 times higher than that of the unmodified one. Finally, a novel molecular synergistic mechanisms for the enhanced SMFC is also presented, based on the higher bacteria number, the capacitive performance of PANI, the hydrogen bond interaction and higher conductivity of MWCNTs. This excellent electrochemical performance makes the MWCNTs/PANI composite be a potential choice for higher output SMFC.     

Preparation and electrochemical properties of sulfur-acetylene black composites as cathode materials

A sulfur-acetylene black (AB) composite was synthesized by thermally treating a mixture of sublimed sulfur and AB. The sulfur-AB composites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) tests. From the results, we confirmed that sulfur was well dispersed on nano-scale and embedded inside nano-pores of the acetylene black with the steric chain structure in the composite. The electrochemical performance of the composite as cathode materials was evaluated by the galvanostatic method, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS). The sulfur-AB composite, which can effectively confine the diffusion of dissolved polysulfides in organic electrolyte and stabilize the structure during the charge and discharge process, showed high capacity and good cycle performance. The discharge capacity of the sulfur-AB composite was maintained at 500 mAh/g after 50 cycles.     

硅/石墨烯基自支撑薄膜的制备及电化学性能

采用简单的超声、抽滤和水合肼化学还原相结合的方法制备硅/石墨烯基自支撑薄膜,系统研究了硅含量对硅/石墨烯复合材料电化学性能的影响。结果表明：通过在石墨烯水凝胶的片层之间插入纳米硅颗粒,可以有效地控制硅体积变化,增加该复合膜的机械强度并提高其导电性。提高硅/石墨烯复合材料中硅含量的比例可以提升其可逆比容量和首次库仑效率,当硅质量分数为53%时,复合膜在0.1C倍率下的可逆比容量及首次库仑效率分别达到945.6mA·h/g和64.8%（纯硅的229倍和9倍）;继续提高硅含量的比例,可以提升其循环寿命（循环50次容量保持率60.9%、质量分数为67%的Si）,但材料比容量有所下降,说明石墨烯在稳定硅基复合材料电化学性能方面发挥着非常重要作用。     

Pt-Ni/MWCNTs复合催化剂的制备及电化学性能研究

采用溶液还原法将铂镍负载于多壁碳纳米管(MWCNTs)制备Pt-Ni/MWCNTs复合催化剂。利用透射电子显微镜(TEM)、 X射线衍射仪(XRD)对复合催化剂进行结构表征,结果表明,铂镍均匀负载到碳纳米管上,Pt-Ni粒子粒径约为2 nm。XRD分析结果表明,复合催化剂是以Pt晶格为基础的固溶体结构。采用循环伏安法和计时电流法在碱性条件下对修饰电极进行电化学性能研究,结果表明,Pt-Ni/MWCNTs可直接催化葡萄糖氧化,催化剂对葡萄糖的灵敏度为571.68 μA•mmol/(L•cm2),线性范围1.0×10-5-8.2×10-3 mol/L (R=0.9994),电极对葡萄糖的最低检测限为0.5 μmol/L(S/N=3),该电极对葡萄糖有良好的电催化氧化性能,且选择性和重现性好,可有效避免抗坏血酸、尿酸和多巴胺的干扰。     

Preparation and enhanced electrochemical properties of nano-sulfur/poly(pyrrole-co-aniline) cathode material for lithium/sulfur batteries

Poly(pyrrole-co-aniline) (PPyA) copolymer nanofibers were prepared by chemical oxidation method with cetyltrimethyl ammonium chloride (CTAC) as template, and the nano-sulfur/poly(pyrrole-co-aniline) (S/PPyA) composite material in lithium batteries was achieved via co-heating the mixture of PPyA and sublimed sulfur at 160 °C for 24 h. The component and structure of the materials were characterized by FTIR, Raman, XRD, and SEM. PPyA with nanofiber network structure was employed as a conductive matrix, adsorbing agent and firm reaction chamber for the sulfur cathode materials. The nano-dispersed composite exhibited a specific capacity up to 1285 mAh g⁻¹ in the initial cycle and remained 866 mAh g⁻¹ after 40 cycles.     

Cure reaction of multi‐walled carbon nanotubes/diglycidyl ether of bisphenol A/2‐ethyl‐4‐methylimidazole (MWCNTs/DGEBA/EMI‐2,4) nanocomposites: effect of carboxylic functionalization of MWCNTs

BACKGROUND: The aim of this work was to study, using differential scanning calorimetry, the effect of carboxylic functionalization of multi‐walled carbon nanotubes (MWCNTs) on the cure reaction of MWCNTs/diglycidyl ether of bisphenol A/2‐ethyl‐4‐methylimidazole (MWCNTs/DGEBA/EMI‐2,4) nanocomposites. This is important for the practical design, analysis and optimization of novel materials processing. RESULTS: Comparing the influence of non‐functionalized MWCNTs and carboxyl‐functionalized MWCNTs, it was found that, at the initial curing stage, both MWCNTs act as catalyst and COOH functionalization of MWCNTs has a catalytic effect on the curing process. Then, at the later curing stage, non‐functionalized MWCNTs prevent the occurrence of vitrification, whereas COOH functionalization of MWCNTs promotes vitrification. Non‐functionalized MWCNTs decrease the degree of curing, as evidenced by lower total heat of reaction and lower glass transition temperatures of nanocomposites compared to neat epoxy; however, COOH functionalization of MWCNTs increases the degree of curing. CONCLUSION: For the development of composites, COOH functionalization of MWCNTs could bring a positive influence to the composite process. Its acceleration of cure could help shorten pre‐cure time or lower pre‐treatment temperature, and its effect of promoting vitrification could help shorten post‐cure time or lower post‐treatment temperature. Copyright © 2009 Society of Chemical Industry     

基于MWCNTs/PA复合材料铜表面处理的传热性能

从换热器防腐和强化传热的角度出发,对铜板表面进行不同的涂膜处理：聚丙烯酸酯（PA）单双面涂膜、MWCNTs/PA复合材料单双面涂膜和无涂层铜板。通过对流换热实验,研究不同处理条件下的传热系数。结果表明,经PA处理过后的铜板传热系数明显降低。与无涂层铜板相比,单、双面PA处理的铜板传热系数分别下降21.91%和40.00%。经MWCNTs/PA复合材料处理过后的铜板传热系数得到了提高。与无涂层铜板相比,单、双面MWCNTs/PA处理的铜板的传热系数分别提高了16.74%、27.49%。     

Confined tailoring of CoFe2O4/MWCNTs hybrid-architectures to tune electromagnetic parameters and microwave absorption with broadened bandwidth

Multi-walled carbon nanotubes (MWCNTs) are highly alluring as an electromagnetic (EM) wave absorber owing to their multi-dimensional structure, high chemical stability, low density, and significant conduction loss, which provide great promises as an excellent EM wave absorber in practical applications. Herein, a simple and controllable solvothermal technique is applied to synthesize cobalt ferrite/MWCNTs (CoFe₂O₄/MWCNTs) hybrid composite. Various analytical techniques were used to investigate the composition, morphological structure, and electromagnetic parameters of the as-prepared hybrid composite. The obtained results revealed that, a strong network of CoFe₂O₄ microspheres interweaved with MWCNTs in the prepared hybrid composite. The resultant CoFe₂O₄/MWCNTs composites achieve a minimum reflection loss (RL_min) of ?50.80 dB at a thickness of 4.2 mm and effective absorption bandwidth (EAB) of 3.36 GHz at a thickness of 1.6 mm exhibiting the superior RL_min compared to the typical magnetic composite derived absorbers. This research advocates the precise development and designing of unique MWCNTs-based composites as a high-efficient and lightweight electromagnetic wave absorber.     

The preparation of conductive nano-LiFePO4/PAS and its electrochemical performance

A simple and effective method has been developed to synthesize a nano-sized LiFePO₄/PAS (polyacenic semiconductor) composite. The LiFePO₄ particles coated and connected by PAS are uniformly distributed in the range of 50-80 nm. The electronic conductivity of this material is as high as 1.2 × 10⁻¹ S/cm due to the conductive network of PAS. In comparison with the micro-LiFePO₄/PAS, the nano-LiFePO₄/PAS exhibits much better rate performance. At the 12-min charge-discharge rate, the power and energy densities of the nano-LiFePO₄/PAS are shown as 2063 W/kg and 412 Wh/kg, which are much higher than those of the micro-LiFePO₄/PAS (1600 W/kg and 320 Wh/kg). It is especially notable that the nano-LiFePO₄/PAS cathode without adding Super P shows similar electrochemical behaviors with the cathode adding Super P at all C-rates. Thus, such cathode without adding Super P will enlarge both the volume energy density and weight energy density of batteries. In addition, this cathode exhibits an excellent long-term cyclability, retaining over 95.4% of its original discharge capacity beyond 500 cycles at 0.2C rate. These favorable electrochemical performances should be attributed to its nanometric particle size and the high electronic conductivity.     

静电纺PVA/PEO/多壁碳纳米管超细纤维的制备与性能

采用超声波辅助溶液共混的方式制备聚乙烯醇/多壁碳纳米管(PVA/MWCNT)复合溶液,并将该溶液与聚氧化乙烯(PEO)溶液共混,利用静电纺丝技术制备PVA/PEO/MWCNTs复合超细纤维。运用扫描电子显微镜(SEM)、X-射线衍射仪(XRD)、示差扫描量热仪(DSC)方法对不同MWCNTs含量的PVA/PEO/MWCNTs复合纤维的微观形貌、结构和热性能进行了观察分析。结果表明:随着MWCNTs含量的增加,纤维直径显著变细,MWCNTs的加入降低了纤维的结晶性,纤维的热稳定性有所提高。     

Enhanced mechanical properties of PDMS/PMMA composite membrane using MWCNTs and its application in phenol separation from saline wastewater

This work describes the enhanced mechanical properties of composite polydimethylsiloxane/poly(methyl methacrylate) (PDMS/PMMA)/multi-walled carbon nanotubes (MWCNTs) nanofiber membrane and its application in the phenol separation from saline wastewater. MWNCTs with varied content were immobilized in the membrane matrix using electric field of electrospinning. The neat PDMS/PMMA and composite PDMS/PMMA/MWCNTs membranes were characterized by scanning electron microscopy, universal testing machine, contact angle measurement, 3D automatic optical profiler, and pore size analyzer. Results indicated that tensile strength of composite PDMS/PMMA/MWNCTs membrane was drastically increased six times with a water contact angle (WCA) of 163.3° due to increased roughness parameters compared to neat membrane. However, porosity and fiber diameter of PDMS/PMMA/MWCTs membrane decreased with the increase of MWCNTs content. Moreover, phenol extraction efficiency of PDMS/PMMA/MWNCTs membrane was found to be 34.5% higher than neat one with similar salt rejection efficiency of 99.97%. The stability of MWCNTs in the membrane matrix was confirmed by the cross-sectional morphology, which indicated the robust and novel design of membrane. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47123.     

Organic binder‐free cathode using FeS2‐MWCNTs composite for thermal batteries

FeS₂ ‐ MWCNTs (Multi‐Walled Carbon NanoTubes) composite without using an organic binder was used as a thin cathode for thermal batteries. A thin cathode with FeS₂ ‐ MWCNTs composite exhibited good mechanical strength without an organic binder. A discharge evaluation of the thin cathode with FeS₂ ‐ MWCNTs composite revealed a discharge capacity 2.3 times that of the pellet type cathode and 1.13 times that of a thin cathode with an organic binder. In addition, the single battery applying a thin cathode with FeS₂ ‐ MWCNTs composite showed a lower total polarization than when applying an organic binder. These results showed that FeS₂ ‐ MWCNTs composite is suitable as a thin cathode for thermal batteries.     

Preparation and performance of a core-shell carbon/sulfur material for lithium/sulfur battery

The core-shell carbon/sulfur material with high performance is prepared by a facile and fast deposit method in an aqueous solution. As sulfur ratio is 85% (w/w) in the composite, scanning electron microscope (SEM) and transmission electron microscope (TEM) observation show that the moniliform particles with 10 nm sulfur shells preserve the morphology of carbon cores. Tested as the cathode material in a lithium cell with binary organic electrolyte at room temperature, the composite shows excellent electrochemical performance. It exhibits a specific capacity up to 1232.5 mAh g⁻¹ at the initial discharge and its specific capacity remained above 800 mAh g⁻¹ after 50 cycles. Meanwhile, the composite also exhibits the high-rate behavior at 800 mA g⁻¹ of current density. Assuming a complete reaction to the final product, Li₂S, the utilization of the electrochemically active sulfur is about 85% at the initial cycle. Electrochemical impedance spectroscopy (EIS) is introduced to understand the impact of the microstructure of composite on electrochemistry. According to our study, a novel core-shell structural carbon/sulfur material is proposed and the key factors of the preparation are discussed.     

膨胀石墨／二氧化钛复合材料的制备与性能研究

本文主要研究了膨胀石墨／二氧化钛复合材料的制备,采用直接膨化的膨胀石墨与钛酸丁酯的醇溶液混合法制备膨胀石墨／二氧化钛复合材料,并分析了膨胀石墨／二氧化钛复合材料的物理性能,以甲基橙溶液的光催化降解反应为探针反应,评价了该复合材料的催化性能。     

水蒸气对MnOx/MWCNTs低温SCR脱硝催化剂的影响

为考察MnOx/MWCNTs催化剂抗水效果,实验研究了水蒸气对其低温NH3-SCR脱硝性能的影响,并通过比表面积(BET),程序升温还原(TPR)和热重(TG)等多种手段对催化剂的结构进行了表征.结果表明,水蒸气存在下,催化剂低温活性明显受到抑制,NOx最高转化率温度向高温方向偏移约30℃.随着水蒸气体积分数的增加和反...     

Enhanced electrochemical performance of silicon-based anode material by using current collector with modified surface morphology

Cycle-life of the mixed silicon-graphite composite electrode, with a specific capacity of about 800 mAh/g, for lithium-ion batteries has significantly been improved by using a Cu current collector with a properly modified surface morphology. Especially, it is found that the electrode slurry-coated on a nodule-type foil exhibits a quite good capacity retention. The enhanced cyclability was attributed to the formation of the micro-columnar structure in the composite electrode layer during charge-discharge cycling. It is suggested that if further optimized current collector system is used with a high-performance Si-based active material, better cycle performance is expected.     

载Pt石墨烯中空微球催化剂的制备及其电催化性能

目前,直接甲醇燃料电池（DMFC）已成为世界各国探寻新型绿色动力源的首选。铂基催化剂虽然被公认为催化甲醇氧化最有效的催化剂,但离其商业化应用仍然存在较大差距。提高铂的利用率和电催化性能被公认为是解决DMFC商业化的关键问题。基于以上考虑,本文采用一种不需要使用表面活性剂的模板辅助法成功合成出了石墨烯中空球,并利用电沉积法负载Pt纳米颗粒。该载Pt石墨烯中空微球具有非常高的比表面积（226.4m2/g）和相互连通的结构。电化学测试结果表明,该载Pt石墨烯中空球的电化学活性表面积高达43.27m2/(g,Pt),峰值电流密度几乎是商业铂碳的两倍,且稳定性明显高于商业化铂碳。该载Pt石墨烯中空球对甲醇氧化展现出了极好的应用前景。     

Controllable preparation of alumina nanorods with improved solid electrolyte electrochemical performance

Alumina powders have been widely used in lithium-ion batteries such as separator coating, electrode surface modification and electrolyte fillers. Rod-like alumina with its special aspect ratio is expected to open up a new application direction. In this work, alumina nanorods were prepared by a facile hydrothermal method. The aspect ratio and morphology of alumina nanorods were optimized by adjusting the hydrothermal temperature, hydrothermal synthesis time, volume ratio, directing agent, and sintering temperature. γ-Al₂O₃ nanorods with a diameter of 200–300 nm and a mean length of 5 μm and α-Al₂O₃ with a diameter of 100–200 nm and mean length of 5 μm were obtained by calcining the alumina precursor (AACH) at 800 °C and 1200 °C, respectively. The prepared alumina nanorods were added into polymer solid electrolyte, which promoted the dissociation of the lithium salt and stabilized the propylene polycarbonate (PPC) polymer, resulting in an improved potential window (4.5 V) and ionic conductivity (3.7 × 10⁻⁴ S/cm) of the PPC-based polymer solid electrolyte (SE). An NCM622/SE/Li solid-state battery showed enhanced electrochemical performance at ambient temperature with an initial discharge capacity of 188.5 mAh/g and a retention capacity of 158.1 mAh/g after 200 cycles at a current density of 0.5 C. These alumina nanorods have potential to be widely used in high-performance solid electrolytes.