炭气凝胶在电化学能源材料中的应用研究进展

炭气凝胶是一种新型、轻质、多孔的非晶态纳米材料,具有在纳米尺度可控和剪裁的连续三维网络结构.简单介绍了炭气凝胶的制备工艺,详细综述了炭气凝胶在电化学超级电容器、燃料电池和锂离子电池等电化学能量储存与转换系统中的主要应用研究进展.     

Metal-doped carbon aerogels as catalysts during ozonation processes in aqueous solutions

The efficiency of Co(II)-, Mn(II)-, and Ti(IV)-doped carbon aerogels for the transformation of ozone into (*)OH radicals was investigated. The carbon aerogels had a markedly acid surface character (pH(PZC approximately equal) congruent with 3-4) with very high surface oxygen concentrations (O approximately equal with 20%). X-ray photoelectron spectroscopy (XPS) analyses of the samples showed the oxidation state of the metals was +2 for Co and Mn and +4 for Ti. The presence of Mn(II)-doped carbon aerogel enhanced ozone transformation into (*)OH radicals, whereas the presence of Co(II) and Ti(IV) carbon aerogels presented no activity in this process. Moreover, it was observed that an increase in the concentration of Mn in the surface of the aerogel increases its efficiency to transform ozone into (*)OH radicals, with an Rct value ([OH]/[O(3)]) of 5.36 x 10(-8) for the aerogel doped with 16% of surface Mn(II) compared to an R(ct) of 2.68 x 10(-9) for conventional ozonation. Regardless of the aerogel used, XPS analysis of the ozonated aerogel samples showed an increase in the concentration of surface oxygen when the exposure to ozone was longer. However, presence of oxidized metal species after ozone treatment was only detected in the case of the Mn-doped aerogel, (Mn(III) and Mn(IV)). CO(2) activation of carbon aerogel produced a marked increase in its efficiency to transform ozone into (*)OH radicals compared with non-activated sample. The efficiency of Mn activated carbon aerogel to transform ozone into (*)OH radicals was greater than that of Witco commercial activated carbon or H(2)O(2) in the ozonation of water from Lake Zurich (Zurich, Switzerland).     

炭气凝胶为电极的超级电容器电化学性能的研究

炭气凝胶电极的电化学测试表明,炭气凝胶具有性能稳定、充放电效率高、适合于大电流充放电等优良性能.炭气凝胶储电的影响因素主要来自于比表面积、孔容和孔结构分布的综合作用.孔容较大,平均孔径较宽时,储电能力较大,且大孔容对电极材料储电是相当有利的.在高比表面积活性炭中添加不同比例的炭气凝胶,可以提高电极的比电容,炭气凝胶含量为15％时,电极比电容最高.     

旧报纸碳基气凝胶的制备及其吸附性能的研究

将富含纤维素的旧报纸先进行润胀、打浆,然后冷冻干燥,得到旧报纸气凝胶（WNA）,利用高温热分解的方式处理WNA制得旧报纸碳基气凝胶（CA）。采用傅里叶变换红外光谱（FT-IR）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）对CA的性能进行表征。结果表明,CA的密度（0.0348 g/cm³）较低,动态接触角为129.8°,表明CA的疏水性能优异。FT-IR结果表明,与WNA相比,CA中羟基、烷基及糖苷键等官能团含量减少。SEM分析表明,CA的纤维宽度在8～10 μm范围内,其具有连续纳米多孔三维网络结构。XRD分析表明,纤维素的结晶区受到破坏,导致无定形碳的形成。CA能高效、快速地吸附有机溶剂和石油化工产品,吸附量可达自身质量的21～37倍。利用燃烧的方法可将吸附的物质从CA中分离出来并对CA进行回收。经过6个吸附/燃烧循环过程,CA对甲醇和硅油的吸附能力分别是原吸附能力的83.9%和86.4%,表明CA可实现多次循环利用。     

硅气凝胶的研究进展

目前硅气凝胶是世界上最轻、隔热性最好、孔隙率较高且声传播速率较低的固体材料,由于其特殊的网络结构使其具有很多独特的性能。本文从其研究历史及现状出发,对其性能以及在不同方面的应用和制备原理进行了综述,并对其广阔的发展前景进行了展望。     

聚氨酯基气凝胶隔热材料研究进展

聚氨酯基气凝胶隔热材料是一类新型隔热材料。聚氨酯分子结构的可设计性和气凝胶独特纳米多孔三维网络结构的有机结合能使聚氨酯基气凝胶材料具有更好的隔热性能。本文介绍了聚氨酯气凝胶、聚脲气凝胶和聚氨酯增强无机物气凝胶材料的研究现状,重点介绍其在隔热性能方面的研究进展。     

A Silica‐Aerogel‐Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus

High‐energy all‐solid‐state lithium (Li) batteries have great potential as next‐generation energy‐storage devices. Among all choices of electrolytes, polymer‐based systems have attracted widespread attention due to their low density, low cost, and excellent processability. However, they are generally mechanically too weak to effectively suppress Li dendrites and have lower ionic conductivity for reasonable kinetics at ambient temperature. Herein, an ultrastrong reinforced composite polymer electrolyte (CPE) is successfully designed and fabricated by introducing a stiff mesoporous SiO₂ aerogel as the backbone for a polymer‐based electrolyte. The interconnected SiO₂ aerogel not only performs as a strong backbone strengthening the whole composite, but also offers large and continuous surfaces for strong anion adsorption, which produces a highly conductive pathway across the composite. As a consequence, a high modulus of ≈0.43 GPa and high ionic conductivity of ≈0.6 mS cm^?1 at 30 °C are simultaneously achieved. Furthermore, LiFePO₄–Li full cells with good cyclability and rate capability at ambient temperature are obtained. Full cells with cathode capacity up to 2.1 mAh cm^?2 are also demonstrated. The aerogel‐reinforced CPE represents a new design principle for solid‐state electrolytes and offers opportunities for future all‐solid‐state Li batteries.     

异氰酸酯增强二氧化硅气凝胶的力学性能

采用有机无机复合的方式,制得异氰酸酯增强的SiO2气凝胶。将硅酸甲酯(TMOS)、甲基三甲氧基硅烷(MTMS)、3-氨丙基三乙氧基硅烷(APTES)配成混合硅源,经水解缩聚后形成凝胶,老化后浸泡在含六亚甲基二异氰酸酯单体(HDI)的乙腈溶液中,最后经CO₂超临界干燥,获得了具有良好机械性能的SiO₂气凝胶。制备过程中引入的MTMS增加了凝胶与有机物间的浸润性,与使用有机物低聚体相比,使用单体可使有机物更易进入凝胶网络,反应更充分,形成纳米尺度更均匀的复合气凝胶。复合后的气凝胶密度为330 mg/cm³、比表面积为446.3 m²/g、热导率为0.068 W•m^-1•K^-1,该气凝胶良好的力学性能(压缩强度为19.96 MPa、压缩模量为82.37 MPa)使气凝胶的机械加工成为可能。     

镍钴/碳气凝胶的制备及电催化析氧性能研究

以海藻酸钠为原料,通过溶胶-凝胶合成法得到不同镍钴比例海藻酸水凝胶,然后通过不同温度的煅烧处理,得到不同比例镍钴/碳气凝胶电极催化剂。采用X-射线衍射(XRD)和扫描电子显微镜(SEM)等手段对产物的结构和形貌进行表征。通过电化学测试研究了各样品的电催化析氧性能和稳定性。结果表明,镍钴质量比为1∶5,275℃温度下的样品电催化析氧性能最好。