多孔碳纤维电极材料的制备及电容去离子性能研究

由于碳纳米纤维比表面积(SSA)较低,在电容去离子(CDI)应用中,其脱盐效率并不理想。该研究采用静电纺丝技术制备了沸石咪唑酯骨架-8(ZIF-8)材料与聚丙烯腈(PAN)复合纳米纤维,并通过碳化工艺处理得到多孔碳纳米纤维电极材料。经过优化组分及碳化工艺后,所得碳纤维电极的SSA和孔体积分别高达398.74 m²/g和0.180 cm³/g。在1.2 V和1.6 V电压下,该电极对500 mg/L的NaCl溶液(50 mL)的盐吸附容量分别达21.16 mg/g和39.04 mg/g。此外,电化学测试结果显示,提高碳纳米纤维电极的孔隙率可以在一定程度上提高双电层电容,从而实现更高的离子吸附量和更稳定的储能性能。     

多壁碳纳米管与氧化石墨对活性炭电化学性能影响

以石油焦制得活性炭（AC）作为超级电容器的电极材料,在此AC中分别加入5％多壁碳纳米管（MW-CNTs）或5％氧化石墨（GO）,借助氮吸附分析仪、循环伏安测试（CV）和电化学交流阻抗谱分析（EIS）,比较MW-CNTs与GO对改进AC电化学性能作用影响.实验结果显示：MWCNTs和GO的吸附等温线具有多段特征,而AC呈现含丰富中孔的微孔炭特征.CV测试显示,在低扫描速率下,加入MWCNTs和GO可使响应电流略有增加.EIS揭示加入MWCNTs和GO可提高AC电极的导电性、频率响应和快速充放电性能,同时提高AC电极的的充放电容量.倍率放电性能和1 000次循环测试也表明加入MWCNTs和GO可提高AC电极的放电容量.     

无粘结剂的柔性硫/碳纤维布电极的制备及电化学性能研究

以碳布为基底,通过浸渍法成功制备了柔性硫/碳纤维布电极.制备的柔性硫/碳纤维布电极无需添加导电剂和粘接剂,可直接用作硫正极极片组装电池,大大简化了电池制备工艺.电化学测试结果表明,硫含量为56.77%(质量分数)的硫/碳纤维布电极展现出了最好的电化学性能,即在0.1A/g电流密度下的可逆放电比容量达1 394mAh/g;充放电循环测试100次后,可逆放电容量仍然维持在733mAh/g.电化学性能的提高主要归因于碳纤维本身的导电性、柔韧性以及大量碳纤维相互交错互联的导电网络.     

钒离子改性MXene的制备及其在锂硫电池中的应用研究

利用化学刻蚀后得到的MXene (MX)片层具有大量阴离子官能团的特点,采用喷雾干燥技术,设计并合成了钒离子改性MXene(MX-VN)材料用于锂硫电池正极。MXene的优异导电性可以提高硫正极整体的导电性,同时原位构建的MX-VN界面可以提高对多硫化物的吸附效果和催化能力,提高硫的利用率。实验结果表明,采用MX-VN/S为正极的锂硫电池在0.1 C下的放电容量高达1438 mAh/g,且在0.5 C下循环200次以后容量保持率高达77.5%,电池性能明显提升。     

广玉兰叶粉及其生物炭对亚甲基蓝的吸附性能研究

将单因素试验与材料表征相结合,探究了广玉兰叶粉及其生物炭的吸附性能及吸附机理。分析结果表明:广玉兰叶粉及其生物炭均为多孔结构且含有丰富的表面官能团,平衡吸附容量分别为109.77 mg/g和105.08 mg/g。pH值升高会提升亚甲基蓝去除率,在pH值为11时,广玉兰叶粉及其生物炭对亚甲基蓝去除率分别为92.63%和90.21%。两种材料均符合朗缪尔(Langmuir)等温吸附模型和二级动力学模型,以单层化学吸附为主,且吸附过程是自发吸热反应。     

两种硫含量控制方法对锂硫电池性能的影响

采用高导电性碳材料和商业活性炭分别作为硫的载体,与单质硫混合后进行热处理制得SP/S和CAC/S硫碳复合材料,利用热重测试、循环伏安、交流阻抗和恒流充放电测试等分析方法,研究了正极中电极材料厚度、硫碳复合比例对电池电化学性能的影响.结果表明:适当增加电极材料厚度可以有效地改善Super-P材料电极综合电化学性能;通过改变硫碳复合比例,提高硫含量则对活性炭材料锂硫电池电极的性能提升有着显著的效果.其中,含硫量为63.60%的CAC/S正极材料首次放电比容量达到908.8 m Ah/g,活性物质利用率为54.2%,100圈循环后放电容量为594.1 m Ah/g,容量保持率达到65.4%.     

锌铜多孔碳复合材料制备及其吸附碘研究

为了提升吸附材料对放射性碘的去除效果，以溶剂热法制备了锌铜双金属有机框架材料(Zn/Cu BTC),并以此为模板可控热解得到了具有高效吸附性能的锌铜纳米多孔碳(Zn/Cu@NPC)材料。使用扫描电子显微镜(SEM)、X射线粉末衍射(XRD)和比表面积分析等手段对材料的形貌结构、物化性质进行表征。结果表明：热解得到的Zn/Cu@NPC保持了Zn/Cu BTC的正八面体拓扑结构，表面出现氧化锌(ZnO)纳米颗粒，过渡金属锌的引入有效提升了材料比表面积。Zn/Cu@NPC表现出优异的碘离子吸附性能，吸附容量为212.5 mg/g,是单金属Cu@NPC吸附容量的3.99倍。该材料耐酸碱性、选择吸附性能良好，且再生循环吸附5次后吸附容量可保持首次吸附的90%。     

水蒸气活化对活性炭电吸附脱盐性能的影响

用硝酸对活性炭进行去灰分处理，并用水蒸气进行二次活化，将活性炭制成电极，在电吸附装置中进行电吸附测试。结果表明，二次活化可以提高活性炭的比表面积和孔容，并使得活性炭的单位吸附量从2.92 mg/g提高到4.55 mg/g。活化效果受活化时间和活化温度共同影响，活化1h 的效果最好，提高活化温度有利于提高吸附性能。     

聚吡咯纳米纤维修饰电极电容法脱盐实验

以恒电位法制备的聚吡咯纳米纤维修饰电极为研究对象,重点考察了电极电容法脱盐过程中工作电压、原料液浓度及电极极间距离等操作条件对电极脱盐效果的影响规律.实验结果表明:在工作电压为0.8~1.6 V范围内,电极的吸附量随工作电压的增加而增大,但增加幅度逐渐减小;当工作电压为1.4 V和1.6 V时,电极的吸附量基本相等且最大,为228.6 mg/m2;原料液质量分数为0.01%~0.1%范围内时,电极的吸附量随原料液浓度的增加而增大,其在溶液质量分数为0.1%时最大,为548.6 mg/m2;电极的吸附量随着电极极间距离的增加而降低,其在极间距离为28 mm时最大,分别是极间距离为35 mm和48 mm时的1.17倍和1.75倍.循环脱盐实验结果表明聚吡咯纳米纤维修饰电极具有显著的循环吸附和脱附能力,显示出良好的实用化应用前景和潜力.     

碳纤维电极的研制

本文详细叙述了碳纤维电极的研制工艺，并对其性能进行了测试，碳纤维电极的峰高均值为268．57μ A/V，变异系数为1．213％。GC电极的峰高均值为37.3μ A/V，变异系数为1．553％，碳纤维电极具有比GC电极更高的稳定性。在5．0mg/L Hg^2 -0.12mole/L盐酸溶液中测量铅，检测限达到0．020μ g/L(电富集600秒)，并且用于血液中痕量铅的测定，标准加入回收率为93．5％。RSD(n＝11)＜8．3％。     

Optimizing the fabrication of carbon nanotube electrode for effective capacitive deionization via electrophoretic deposition strategy

In order to obtain superior electrode performances in capacitive deionization(CDI), the electrophoretic deposition(EPD) was introduced as a novel strategy for the fabrication of carbon nanotube(CNT) electrode.Preparation parameters, including the concentration of slurry components, deposition time and electric field intensity, were mainly investigated and optimized in terms of electrochemical characteristic and desalination performance of the deposited CNT electrode. The SEM image shows that the CNT material was deposited homogeneously on the current collector and a non-crack surface of the electrode was obtained. An optimal preparation condition of the deposited CNT electrode was obtained and specified as the Al(NO3)3 M concentration of 1.3 × 10~(-2) mol/L, the deposition time of 30 min and the electric field intensity of 15 V/cm. The obtained electrode performs an increasing specific mass capacitance of 33.36 F/g and specific adsorption capacity of 23.93 mg/g, which are 1.62 and 1.85 times those of the coated electrode respectively. The good performance of the deposited CNT electrode indicates the promising application of the EPD methodology in subsequent research and fabrication of the CDI electrodes for CDI process.     

电化学极化对活性炭纤维吸附SCN-的影响

为了去除冶金工业废水中的有害成份,研究活性炭纤维(ACF)电吸附技术。以SCN-为模型物,采用三电极电解池以紫外分光光度法(UV)检测电化学极化对吸附SCN-的影响。实验结果表明,正极化可以强化ACF对SCN-的吸附,而负极化减弱对SCN-的吸附,这一电吸附现象在一定程度上具有可逆性。L angm u ir方程可以描述ACF对SCN-的吸附和电吸附的平衡线。吸附动力学实验表明,与未极化比较,电吸附时ACF在开始阶段(30m in内)能够较快地达到较高的吸附量,使溶液中的SCN-浓度迅速降低。再生过程正极化还可以使活性炭纤维的孔径增大,从而增强活性炭纤维的吸附量。     

原位碳包覆增强铜纳米线的化学稳定性

铜纳米线（CuNWs）具有成本低、导电性高、透明及柔韧性好等优点,且铜元素在地表储量丰富,是极为理想的电极材料,特别是用作于柔性及透明电极。然而铜纳米线稳定性差,极易被空气氧化和受化学环境腐蚀,这极大的限制了它们的实际应用。在本文中,我们提出了一种利用水热碳化方法在铜纳米线表面进行原位碳包覆的保护策略,可以有效地增强其化学稳定性。我们系统研究了影响碳膜生长的各种因素,包括葡萄糖前驱体浓度（碳源）、水热温度及水热时间等。我们发现在葡萄糖浓度为 80 mg·mL?1左右,水热温度为 160–170°C,水热时间为1–3 h的条件下,可以在铜纳米线表面均匀生长厚度为3–8 nm的碳膜。所制备的碳包覆铜纳米线（CuNWs@C）表现出优异的抗氧化和抗腐蚀稳定性,在光电子器件领域具有广阔的应用潜力。     

Adsorption properties of Ⅴ(Ⅳ) on resin-activated carbon composite electrodes in capacitive deionization

Composite electrodes prepared by cation exchange resins and activated carbon(AC) were used to adsorb V(IV) in capacitive deionization(CDI). The electrode made of middle resin size(D860/AC M) had the largest specific surface area and mesoporous content than two other composite electrodes. Electrochemical analysis showed that D860/AC M presents higher specific capacitance and electrical double layer capacitor than the others, and significantly lower internal diffusion impedance. Thus, D860/AC M exhibits the highest adsorption capacity and rate of V(IV) among three electrodes. The intra-particle diffusion model fits well in the initial adsorption stage, while the liquid film diffusion model is more suitable for fitting at the later stage. The pseudo-second-order kinetic model is suited for the entire adsorption process. The adsorption of V(IV) on the composite electrode follows that of the Freundlich isotherm. Thermodynamic analysis indicates that the adsorption of V(IV) is an exothermic process with entropy reduction, and the electric field force plays a dominant role in the CDI process. This work aims to improve our understanding of the ion adsorption behaviors and mechanisms on the composite electrodes in CDI.     

Adsorption properties of V(Ⅳ) on resin-activated carbon composite electrodes in capacitive deionization

Composite electrodes prepared by cation exchange resins and activated carbon (AC) were used to adsorb V(Ⅳ) in capacitive deion-ization (CDI). The electrode made of middle resin size (D860/AC M) had the largest specific surface area and mesoporous content than two other composite electrodes. Electrochemical analysis showed that D860/AC M presents higher specific capacitance and electrical double layer capacitor than the others, and significantly lower internal diffusion impedance. Thus, D860/AC M exhibits the highest adsorption capacity and rate of V(Ⅳ) among three electrodes. The intra-particle diffusion model fits well in the initial adsorption stage, while the liquid film diffusion model is more suitable for fitting at the later stage. The pseudo-second-order kinetic model is suited for the entire adsorption process. The ad-sorption of V(Ⅳ) on the composite electrode follows that of the Freundlich isotherm. Thermodynamic analysis indicates that the adsorption of V(Ⅳ) is an exothermic process with entropy reduction, and the electric field force plays a dominant role in the CDI process. This work aims to improve our understanding of the ion adsorption behaviors and mechanisms on the composite electrodes in CDI.     

Si@CNT纳米结构与MOF衍生多孔碳的链状化合物作为锂离子电池负极材料的研究

Silicon anodes are considered to have great prospects for use in batteries; however, many of their defects still need to be improved. The preparation of hybrid materials based on porous carbon is one of the effective ways to alleviate the adverse impact resulting from the volume change and the inferior electronic conductivity of a silicon electrode. Herein, a chain-like carbon cluster structure is prepared, in which MOF-derived porous carbon acts as a shell structure to integrally encapsulate Si nanoparticles, and CNTs play a role in connecting carbon shells. Based on the exclusive structure, the carbon shell can accommodate the volume expansion more effectively, and CNTs can improve the overall stability and conductivity. The resulting composite reveals excellent rate capacity and enhanced cycling stability; in particular, a capacity of 732 mA·h·g?1 at 2 A·g?1 is achieved with a reservation rate of 72.3% after cycling 100 times at 1 A·g?1.     

丝网结构对连通容器抑爆效果的影响

为了考查多层丝网结构对连通容器内气体爆炸的抑制作用,以甲烷-空气混合物为研究对象,利用0.022m3和0.113m3 2个球形容器与一段2m长的管道构成的连通容器进行了一系列丝网结构的抑爆实验,对比分析了20,40,60目和1,3,5,7,9层等不同丝网结构对连通容器的抑爆效果,并通过理论分析和数据处理得到最佳的抑爆结构。结果表明,丝网结构对传爆容器中的爆炸强度的影响要大于起爆容器;当丝网层数较少时,目数对大、小球的爆炸压力影响较小,丝网结构对连通容器不但没有抑爆作用,反而有增加爆炸强度的作用;当丝网层数较多时,目数对大、小球的爆炸压力影响较大;当丝网目数相同时,层数越多,爆炸抑制效果越好。实验条件下,5层和7层分别是40目和60目丝网结构抑爆的临界层数;与5层40目丝网结构相比,7层60目的丝网抑爆效果更好。因此,在实际设计中,应根据其综合作用选择最佳的抑爆结构。     

孔道结构对有序介孔炭电化学性能的影响

以三嵌段共聚物（F127）为模板剂,间苯二酚（R）和甲醛（F）为碳前驱体,在外加的酸性条件下通过自组装的方法制得了F127/RF复合材料,然后经碳化处理得到具有高度有序孔道结构的介孔炭材料（OMCs）,通过XRD、TEM、N₂吸/脱附手段(77K低温下)对其进行结构表征。测试结果表明有序介孔炭材料的BET比表面积和总孔体积分别为770m²/g和0.65cm³/g。以有序介孔炭材料为电极制备超级电容器,对其进行直流恒流充放电测试、循环伏安测试和交流阻抗测试,结果显示在电流密度为0.02A/g时OMC-3比容量为130F/g,100次充放电循环后电容量保持率在99%以上。     

Building well-defined hierarchical nanostructures for sulfur and silicon electrodes

Huge volume expansion of electrode materials (e.g. 80% for sulfur and 310% for silicon) in the electrochemical lithiation reaction is seen as a root-cause of fast capacity fading of rechargeable lithium batteries. In this work, an effective solution is demonstrated by fabricating thin film sulfur and silicon electrodes with hierarchical structure of sulfur (or silicon) particles sandwiched between adjacent reduced graphene oxide (rGO) layers. The hierarchical films are constructed via vacuum filtration assisted layer-by-layer assembly of rGO and the respective precursor particles, i.e. zinc sulfide or silica shelled by super-sticky polydopamine. Polydopamine serves as a glue of rGO layers to furnish good mechanical integrity to the structure, and the precursor of nitrogen-doped carbon upon high-temperature calcination to ensure the electrical contacts between rGO layers. Zinc sulfide is oxidized to the electrochemically active sulfur by soaking in ferric aqueous solution, while silica is reduced to nanosized silicon in magnesium vapor at high temperature. The electrochemical studies reveal that the binder-free hierarchical electrodes can tolerate the volume change upon lithiation/delithiation, giving high initial Coulombic efficiency and good capacity retention. The rGO layers in the sulfur electrode is also found to effectively mitigate the diffusion of polysulfides into electrolyte.