Double carbon decorated lithium titanate as anode material with high rate performance for lithium-ion batteries

Spinel lithium titanate(Li_4Ti_5O_(12)) has the advantages of structural stability, however it suffers the disadvantages of low lithium-ion diffusion coefficient as well as low conductivity. In order to solve issues,we reported a simple method to prepare carbon-coated Li_4Ti_5O_(12)/CNTs(C@Li_4Ti_5O_(12)/CNTs) using stearic acid as surfactant and carbon source to prepare carbon coated nanosized particles. The obtained Li_4Ti_5O_(12) particles of 100 nm in size are coated with the carbon layers pyrolyzed from stearic acid and dispersed in CNTs matrix homogeneously. These results show that the synthesized C@Li_4Ti_5O_(12)/CNTs material used as anode materials for lithium ion batteries, presenting a better high-rate performance(147 m Ahg~(-1)at20 C). The key factors affecting the high-rate properties of the C@Li_4Ti_5O_(12)/CNTs composite may be related to the synergistic effects of the CNTs matrix and the carbon- coating layers with conductivity enhancement. Additionally, the amorphous carbon coating is an effective route to ameliorate the rate capability of Li_4Ti_5O_(12)/CNTs.     

CoO/SnO2@NC/S复合材料的制备及其应用于高稳定性锂硫电池正极材料

To improve the sulfur loading capacity of lithium-sulfur batteries (Li–S batteries) cathode and avoid the inevitable “shuttle effect”, hollow N doped carbon coated CoO/SnO₂ (CoO/SnO₂@NC) composite has been designed and prepared by a hydrothermal-calcination method. The specific surface area of CoO/SnO₂@NC composite is 85.464 m2·g–1, and the pore volume is 0.1189 cm3·g–1. The hollow core-shell structure as a carrier has a sulfur loading amount of 66.10%. The initial specific capacity of the assembled Li–S batteries is 395.7 mAh·g–1 at 0.2 C, which maintains 302.7 mAh·g–1 after 400 cycles. When the rate increases to 2.5 C, the specific capacity still has 221.2 mAh·g–1. The excellent lithium storage performance is attributed to the core-shell structure with high specific surface area and porosity. This structure effectively increases the sulfur loading, enhances the chemical adsorption of lithium polysulfides, and reduces direct contact between CoO/SnO₂ and the electrolyte.     

石墨烯包覆SnO2空心球的制备及其锂离子电池负极性能

以K2SnO3为原料,采用简单的水热反应,通过基于静电引力的自组装机制,制得石墨烯包覆SnO2空心球的复合材料.采用SEM、TEM、XRD、N2吸附等温线研究了复合材料的形貌和结构;采用电化学方法研究了复合材料的锂离子电池负极性能.结果表明,复合材料为石墨烯包覆的直径约200～300nm的SnO2空心球,比表面积为140.1 m2·g-1.当放电电流密度为158m A·g-1时,充电比容量为425 mAh·g-1,库伦效率保持为92%以上,复合材料具有良好的循环性能.     

多功能复合微球及中空微球的制备与性能

摘要：采用磺化聚苯乙烯（Ps）微球为模板制备出了以Fe304-PANi（聚苯胺）为壳,PS为核的具有核壳结构多功能Fe304．PANi／PS复合微球．采用溶剂抽提溶解去除Ps核得到Fe304．PANi具有导电导磁双功能中空微球．中空微球空腔尺寸大小一致,约为190nm,壳层厚度约30nm．通过控制Ps模板磺化时间来同步控制微球空腔大小和微球壳层厚度．Fe304-PANi／PS复合微球及中空微球具有良好的导电性和超顺磁性．所制备的中空Fe304微球及中空Fe304-PANi微球对模拟污水浊度去除率分别达到84．2％及86．9％．     

多孔单晶CeO2空壳球的制备及其CO催化氧化性能研究

以水热法成功制备了(110)面暴露的高活性多孔单晶CeO2空壳球催化剂样品,研究了其形成过程并提出了相应的形成机理.通过X射线衍射、透射电镜及低温氮气吸附/脱附等温线对催化剂结构进行了详细的表征,结果表明:该材料具有多孔结构以及较高的比表面积(259 m2/g).该多孔单晶CeO2催化剂在CO氧化转化中显示了较好的催化性能,其催化活性远高于商业化CeO2,这主要归结于其特殊的(110)高能面的暴露以及多孔单晶结构.     

介孔氧化铝空心球的制备及表征

以掺氮碳球为硬模板,F127为软模板,廉价的Al(NO3)3·9H2O为铝源,成功制备出具有介孔结构的氧化铝空心球。通过SEM,N2吸附-脱附,XRD,FT-IR表征显示,其粒径大小均一,均在500nm左右;壳层具有蠕虫状的介孔结构,且主要为无定型结构的氧化铝;介孔孔径为17nm,比表面积为153m2/g,孔容为0.67cm3/g。详细讨论了介孔氧化铝空心球的形成机理。     

Facile synthesis of polypyrrole nanowires for high-performance supercapacitor electrode materials

Polypyrrole nanowires are facile synthesized under a mild condition with FeCl_3 as an oxidant. Polypyrrole nanowires with the width of 120 nm form many nanogaps or pores due to the intertwined nanostructures. More importantly, PPy nanowires were further applied for supercapacitor electrode materials.After electrochemical testing, it was observed that the PPy nanowire based electrode showed a large specific capacitance(420 Fg~(-1), 1.5 Ag~(-1)) and good rate capability(272 Fg~(-1), 18.0 Ag~(-1)), which is larger than that of most of published results. The as-prepared electrode can work well even after 8000 cycles at 1.5 Ag~(-1).     

NiO nanosheet assembles for supercapacitor electrode materials

In this paper, large scale hierarchically assembled Ni O nanosheets have been favorably fabricated through a facile hydrothermal route. The as-prepared Ni O nanosheet assembles were characterized in detail by various analytical techniques. The results showed these nanosheets present the thickness of about 30 nm and the surface area is 116.9 m~2 g~(-1). These NiO nanosheet assembles were used as the working electrode materials in electrochemical tests, which demonstrated a specific capacitance value of 81.67 Fg ~(-1)at the current density of 0.5 Ag~(-1)and excellent long cycle-life stability with 78.5% of its discharge specific capacitance retention after 3000 cycles at the current density of 0.5 Ag~(-1), revealing the as-synthesized NiO nanosheet assembles might be a promising electrode material for supercapacitor applications.     

囊泡模板法制备纳米/微米级酚醛树脂中空球

以十六烷基三甲基溴化铵(CTAB)和十二烷基硫酸钠(SDS)分子自组装形成的囊泡为模板, 用氨水溶液提供缓冲环境, 甲阶酚醛树脂为前驱体, 控制表面活性剂配比, 反应温度和时间不变, 通过改变搅拌速率得到纳米/微米级酚醛树脂多层中空球, 并利用X射线衍射仪（XRD）、 透射电子显微镜（TEM）、 扫描电子显微镜（SEM）、 比表面积和孔隙分析仪、 热重分析仪（TGA）对所得微球进行表征. 结果表明： 酚醛树脂中空纳米球的粒径为50~60 nm, 球壳厚度约为10 nm； 酚醛树脂中空微米球分为单室和多室两种形貌, 单室中空球粒径为2~5 μm, 多室中空球粒径可达10 μm, 球壳厚度约为500 nm; 两种形貌的酚醛树脂中空球的球壳均为多层周期结构.     

囊泡模板法制备纳米/微米级酚醛树脂中空球

以十六烷基三甲基溴化铵(CTAB)和十二烷基硫酸钠(SDS)分子自组装形成的囊泡为模板, 用氨水溶液提供缓冲环境, 甲阶酚醛树脂为前驱体, 控制表面活性剂配比, 反应温度和时间不变, 通过改变搅拌速率得到纳米/微米级酚醛树脂多层中空球, 并利用X射线衍射仪（XRD）、 透射电子显微镜（TEM）、 扫描电子显微镜（SEM）、 比表面积和孔隙分析仪、 热重分析仪（TGA）对所得微球进行表征. 结果表明： 酚醛树脂中空纳米球的粒径为50~60 nm, 球壳厚度约为10 nm; 酚醛树脂中空微米球分为单室和多室两种形貌, 单室中空球粒径为2~5 μm, 多室中空球粒径可达10 μm, 球壳厚度约为500 nm; 两种形貌的酚醛树脂中空球的球壳均为多层周期结构.     

Porous Fe-Mn-O nanocomposites: Synthesis and supercapacitor electrode application

Transition metal oxide micro-/nanostructures demonstrate high potential applications in energy storage devices. Here, we report a facile synthesis of highly homogeneous oxide composites with porous structure via a coordination polymer precursor, which was prepared with the assistance of tartaric acid.The typical product, Fe-Mn-O composite was demonstrated here. The obtained Fe-Mn-O product was systemically characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, elemental mapping analysis, and X-ray photoelectron spectroscopy. It was demonstrated that the Fe-Mn-O nanocomposite shows interconnected porous structure, in which iron,manganese, and oxygen are uniformly distributed. In addition, the Fe-Mn-O nanocomposite was then fabricated as capacitor electrodes. Operating in an aqueous neutral solution, the Fe-Mn-O composite electrodes showed an wide working potential window from 0.2 to 1.0 V(vs. SCE), and a specific capacitance of 86.7 Fg~(-1)or 0.4 Fcm~(-2)at a constant current density of 1 Ag~(-1)with good cycle life. This study offers a new precursor approach to prepare porous metal oxide composites, which would be applied in energy-storage/conversion devices, catalysts, sensors, and so on.     

水热和硬模板辅助制备氧化铝空心球

以葡萄糖和硝酸铝为原料,采用水热和硬模板辅助技术成功制备了氧化铝空心球。分别通过葡萄糖催化聚合-原位离子吸附一步进行(一步法)或葡萄糖聚合成球-离子吸附分步进行(二步法)制备铝碳复合球壳结构,然后经分步煅烧氧化制得氧化铝空心球。进一步对产物表征结果表明:二步法得到的空心球壳结构稳定紧凑,大小均一,粒径在亚微米级;而一步法步骤简单,操作快捷,但产物结构疏松,粒径在微米级,空心球比二步法有序度要高。此外,对氧化铝空心球结构的形成过程和可能的机理以及二步法中碳球表面基团进行了分析和探讨。     

酚醛树脂基中空碳球的制备

以磺化聚苯乙烯为模板,酚醛树脂为前驱体,利用模板法制备了球壳厚度为50～85nm的中空碳球。采用红外光谱（FT IR）表征聚苯乙烯的磺化程度,并借助扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究中空碳球的中空结构。结果表明,随着磺化时间的增加,中空碳球的直径和球壳厚度都有增加的趋势;当磺化时间小于2?h,形成的球壳较薄,在碳化过程中容易发生塌缩。酚醛树脂的加入量也影响中空碳球的直径与球壳厚度。当酚醛树脂加入量较少时,球壳容易发生破裂。     

新型混凝土砌块EPS复合墙体抗剪承载力的计算

新型混凝土砌块EPS复合墙体是由轻质混凝土空心砌块做为外模,EPS混合土做为内模组合而成。为研究该新型墙体的抗剪性能,本文设计了不同高宽比、竖向正应力、以及不同内芯强度的该新型复合墙体1/2缩尺模型共6片,通过低周反复试验得出该新型复合墙体极限抗剪强度,采用以该新型复合墙体抗压强度的函数来表示其抗剪强度。对实测数据回归分析,建立出适合该新型墙体的抗剪理论计算公式:V_u≤1/(0.281+1.255λ)(0.20(f_(G,m)~(1/2))bh_0+0.12N),该公式具有一定的理论依据和实用价值,可供实际工程设计参考使用。     

CdO孔材料的模板法制备及催化性能研究

采用一步水热方法合成了C/CdS复合微球,经焙烧处理后得到CdO孔材料.使用电子扫描电镜、红外光谱、X射线粉末衍射等手段对C/CdS复合微球和CdO孔材料进行了表征,探讨了产品的形成机理,并研究了CdO作为火箭推进剂的燃速催化剂的性能.结果表明,CdO孔材料能使高氯酸铵高温分解温度降低67.65℃,具有很好的催化活性.     

球形多孔氧化钴/碳复合材料的制备及电容性能研究

采用水热合成和煅烧制备氧化钴/碳(Co3O4/C)复合材料,通过SEM、XRD、N2吸附实验等对该材料进行表征.制备的Co3O4/C复合材料为5μm大小,孔径约为30nm的多孔球形结构.在6mol/L的氢氧化钾溶液中进行电化学测试.结果表明,Co3O4/C复合材料具有良好的电容性能.在电流密度为1A/g时,比电容为143F/g.此外,Co3O4/C复合材料还表现出良好的循环稳定性,在1A/g的电流密度下,充放电循环1000次后,比电容保持率为77.8%.     

碳/氧化锌纳米线阵列/泡沫石墨烯电化学检测叶酸

通过化学气相沉积法制备三维(3D)泡沫石墨烯(GF),然后利用水热合成法在泡沫石墨烯表面生长氧化锌纳米线阵列(ZnO NWAs),再利用化学气相沉积法在其表面沉积碳(C),得到碳/氧化锌纳米线阵列/泡沫石墨烯(C/ZnO NWAs/GF)复合材料.用该复合材料做电极,采用电化学方法检测叶酸(FA).结果表明,三维泡沫石墨烯具有和模板泡沫镍一样的三维孔状结构,ZnO NWAs均匀且垂直地生长在泡沫石墨烯表面,碳沉积在ZnO NWAs表面.在线性范围为0~60 μmol·L-1内,C/ZnO NWAs/GF电极检测FA时,灵敏度为0.13 μA·μmol-1·L,且在尿酸(UA)干扰下检测 FA具有良好的选择性.C/ZnO NWAs/GF电极有良好的稳定性和重复性.     

用微量汞提高测银灵敏度——玻碳电极溶出伏安法

当微量Ag~1、Hg~(2+)(10~(-7)M～10~(-9)M)共存于溶液(用HCl调pH为2的0.1MKSCN)中时,用普通极谱仪在-1.5V(VS、Ag/AgCl、盐桥联接),电解沉积2～10分钟,-0.3V～+0.2V溶出,在+0.12V出现一个很好的Ag-Hg金属间化合物溶出峰,它比Ag~+或Hg~(2+)单独存在时的溶出峰灵敏得多,并与两者的峰高、峰形、峰电位都有显著不同。当Hg~(2+)浓度一定时、峰高与Ag~+浓度呈正比,反之亦然。用标准加入外推法外延工作曲线至横轴,便能直接读出被测液中Ag~+浓度。     

A facile method to synthesize 3D structured Sn anode material with excellent electrochemical performance for lithium-ion batteries

Sn anode materials with high specific capacity are an appealing alternative to graphite for next-generation advanced lithium-ion batteries. However, poor electrochemical performance originating from fracture and pulverization due to the enormous volume changes during lithium alloying/dealloying hinders their commercial applications. Here, we propose the synthesis of a novel 3D structured Sn anode material by a facile method: heat treatment of nanosized SnO₂ spheres in a tube furnace with a flowing mixed atmosphere of C₂H₂/Ar at 400 °C. After the heat treatment, the nanosized SnO₂ spheres convert into pure Sn bulk material (~20 μm), which consists of Sn nanowires (~50 nm in diameter and several microns in length). This unique 3D structure with sufficient voids between the nanowires effectively mitigates the volume expansion of Sn bulk material and ensures good electrical contact between the anode material and conducting additives. As a consequence, the 3D structured Sn anode material exhibits a specific reversible capacity of ~600 mA h/g and no significant capacity degradation (compared with that of the 20th cycle) over 500 cycles at 0.2 C.     

新型PVC膜银离子选择电极的研制及应用

以合成的双(N-乙基-N-苯基氨基二硫代甲酸)1,3-丙二醇酯为载体,采用双层膜电位法直接测定了溶剂聚合物膜中载体与金属离子的络合物生成常数.制备并考察了以双(N-乙基-N-苯基氨基二硫代甲酸)1,3-丙二醇酯为载体的银离子选择电极的性能.实验结果表明:该选择电极对银离子有良好的响应性能和高选择性,在10-3~10-6mol/L的浓度范围内响应斜率为56.0 mV/paAg+,检测下限为3.7×10-7mol/L,碱金属、碱土金属及过渡金属离子不干扰银的测定.该电极可作为测定维生素B1药片中维生素B1含量的电位滴定指示电极和水样中银离子含量的直接测定.