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.     

炭气凝胶的制备及其在超级电容器中的应用研究进展

综述炭气凝胶的制备工艺,介绍炭气凝胶在超级电容器中的应用,论述了炭气凝胶制备工艺-结构-电极性能的关系.     

木质素酚醛基炭气凝胶的制备及电化学性能

以木质素、苯酚和甲醛为原料,NaOH为催化剂,溶胶凝胶法制备了木质素酚醛基有机凝胶,经CO2超临界干燥及高温炭化得到了炭气凝胶(LPCA)。采用扫描电镜(SEM)、比表面及孔结构分析仪表征了材料的结构,通过恒流充放电测试了炭材料的电化学性能。结果表明,制备得到的炭气凝胶以微孔和中孔为主,比表面积达356.6m2/g,首次放电比容量为583.94mAh/g,充放电循环30次比容量未见明显的衰减。     

RF炭气凝胶孔结构的控制及其电化学性能研究

考察了在以间苯二酚(R)和甲醛(F)为原料,碳酸钠(C)为碱性催化剂,通过溶胶.凝胶过程和常压干燥方法制备RF炭气凝胶过程中CO2活化对炭气凝胶孔结构的影响,并通过恒流充放电和循环伏安法测试其电化学性能.结果表明:CO2活化可明显提高炭气凝胶BET比表面积(SBET)和孔容(Vtotal).RF炭气凝胶在900℃下活化3h,SBET从未活化时的633m2/g提高到1271m2/g;相应的电化学测试结果表明,以1mA/cm2的电流充放电,其比电容可从未活化样的81F/g增加到172F/g;以30mA/cm2的电流进行充放电试验,活化样的比电容仍可达到131 F/g.     

炭气凝胶电极电吸附脱盐性能的研究

以间苯二酚和甲醛为原料,通过溶胶-凝胶反应、超临界干燥、炭化等工艺合成制备出炭气凝胶,对炭气凝胶的微观结构进行了表征,并研究了炭气凝胶电极在不同电压和在不同浓度NaCl溶液中的电吸附性能。实验结果表明炭气凝胶电极具有很高的吸附效率,在20min内基本达到吸附平衡。随着外加电压的加大,处理溶液浓度的升高,炭气凝胶电极吸附平衡时间减小,单位吸附量增加,吸附单元内电流增加。     

掺杂钛炭气凝胶电极的制备及电吸附脱盐性能的研究

以间苯二酚、甲醛、钛酸丁酯为原料,分别采用乙醇、异丙醇和水作为溶剂,通过溶胶-凝胶、超临界干燥、高温炭化制备掺杂钛炭气凝胶。通过XRD和TEM分析表明,以乙醇为溶剂可以制备出均匀掺杂锐钛矿晶型的TiO2纳米粒子的炭气凝胶。将制得的掺杂钛炭气凝胶电极应用于电吸附模块进行电吸附脱盐实验,考察了掺杂钛量、电压、溶液浓度对电吸附的影响,以及掺杂钛炭气凝胶电极的循环再生性能。结果表明掺杂TiO2可以极大地抑制物理吸附和提高电吸附量,掺杂20%TiO2的炭气凝胶单位电吸附量是不掺杂TiO2时的4.5倍,其总吸附量接近11mg/g,是一种理想的电吸附电极材料。在1.5V电压下溶液浓度的提高可以提高吸附量,并且经过12次吸附再生过程后掺杂钛炭气凝胶电极的电吸附性能仍然保持稳定,可循环再生性能良好。     

常压干燥制备炭气凝胶及其电化学行为的研究

以甲酚为原料，添加适量的间苯二酚，在氢氧化钠催化作用下与甲醛聚合，经溶胶凝胶、溶剂置换、常压干燥和900℃炭化过程可制备纳米多孔材料炭气凝胶。N2吸附测试表明所制备炭气凝胶BET比表面积高于500m^2／g，在8nm～20nm范围具有集中的孔径分布，适合于做双电层电容器的电极材料。采用电化学阻抗谱测试电极的电化学行为，结果显示炭气凝胶电极在1mol／L的H2SO4电解液中的体积比电容接近70F／cm^3，质量比电容最高达97F／g。     

Co/MR氮掺杂炭气凝胶的制备、结构及氧还原性能

以三聚氰胺、间苯二酚、甲醛为原料,采用溶胶-凝胶法、冷冻干燥等步骤制备出三聚氰胺-间苯二酚-甲醛(MR)干凝胶;并以所制炭气凝胶为载体浸渍硝酸钴,经氮气中高温炭化,得到钴复合氮掺杂的炭气凝胶。考察间苯二酚和三聚氰胺比例、凝胶pH值及炭化条件等对气凝胶结构和催化氧还原活性的影响,采用XRD、XPS、低温氮气吸脱附等方法研究催化剂的结构。随pH值增加,MR气凝胶的介孔分布向小孔移动;当M/R物质的量比为6∶1时,其介孔分布为3.0~4.0 nm。钴复合炭气凝胶多孔结构中存在均匀分布Co金属颗粒和管状炭,Co金属颗粒粒径随炭化温度升高而增加。采用旋转圆盘电极研究催化剂在0.5mol/L H2SO4溶液中的电化学性能,结果表明催化剂具有良好的氧还原活性。     

负载Ni炭气凝胶的制备及结构性能研究

以间苯二酚、甲醛为原料,添加适量的十二烷基苯磺酸钠,再加入不同浓度的乙酸镍溶液,在85℃水浴中聚合;经溶胶-凝胶、溶剂置换、常压干燥和1000℃氮气气氛下热解,得到负载不同含量金属Ni的炭气凝胶.利用透射电镜(TEM)、扫描电境(SEM)、X射线衍射(XRD)、比表面积及孔径分析(BET)和直流充放电测试等手段,对比讨论了负载不同含量金属Ni对炭气凝胶的结构和性能的影响.结果表明,这种方法可以均匀地将Ni纳米粒子分散于炭气凝胶中;适量的金属Ni可使发气凝胶的比表面积及充放电性能得到显著提高;如负载Ni含量过高则炭气凝胶石墨化程度增加.     

常压干燥法制备的炭气凝胶的电化学性能研究

采用常压干燥法制备了炭气凝胶,对所制得的炭气凝胶进行了电化学性能的测试,并与日本进口的超级电容器用超级活性炭进行比较.实验结果表明,炭气凝胶具有优良的电容性能,电双层比电容量和高扫描速度下(100mV/s)的质量比电容量分别达到21μF/cm2和89F/g,高于日本进口超级电容器用超级活性炭.     

Nano-sized Ni-doped carbon aerogel for supercapacitor

Carbon aerogel was prepared by polycondensation of resorcinol with formaldehyde using sodium carbonate as a catalyst in ambient conditions. Nano-sized Ni-doped carbon aerogel was then prepared by a precipitation method in an ethanol solvent. In order to elucidate the effect of nickel content on electrochemical properties, Ni-doped carbon aerogels (21, 35, 60, and 82 wt%) were prepared and their performance for supercapacitor electrode was investigated. Electrochemical properties of Ni-doped carbon aerogel electrodes were measured by cyclic voltammetry at a scan rate of 10 mV/sec and charge/discharge test at constant current of 1 A/g in 6 M KOH electrolyte. Among the samples prepared, 35 wt% Ni-doped carbon aerogel (Ni/CA-35) showed the highest capacitance (110 F/g) and excellent charge/discharge behavior. The enhanced capacitance of Ni-doped carbon aerogel was attributed to the faradaic redox reactions of nano-sized nickel oxide. Moreover, Ni-doped carbon aerogel exhibited quite stable cyclability, indicating long-term electrochemical stability.     

对苯二酚增强纤维素/石墨烯电极的制备

目的 以纳米纤维素气凝胶为骨架,对苯二酚为增强相,并加入还原氧化石墨烯,制备纳米纤维素/还原氧化石墨烯复合电极薄膜,将其应用于超级电容器。方法 采用超声处理制备纳米纤维素/氧化石墨烯混合溶液;在高温高压的环境下,加入对苯二酚,采用水热合成法和冷冻干燥法制备纳米纤维素/还原氧化石墨烯气凝胶,并最终制成电极膜。结果 在纳米纤维素/还原氧化石墨烯复合气凝胶中,石墨烯可将纳米纤维素均匀包裹,形成三维多孔网络结构;纳米纤维素/还原氧化石墨烯复合电极具有良好的电化学性能,在1 mol/L的H2SO4溶液中,当电流扫描速率为1 mA/cm2时,超级电容器比面积电容高达1.621 F/cm2,且在2000次循环测试后,电容保留率为88.3％。结论 以纳米纤维素为基体制备的纳米纤维素/还原氧化石墨复合电极具有良好的电化学性能,可以用作超级电容器电极。     

电化学电容器碳基电极材料研究进展

综述了应用于电化学电容器的各种新型碳材料（活性碳粉、碳气凝胶、碳纳米管）的制备方法、材料特性、电化学性能，提出了在选择电容器碳基电极时需要遵循的几项原则。     

纤维素纳米纤丝-还原氧化石墨烯/聚苯胺气凝胶柔性电极复合材料的制备与性能

利用高长径比的纤维素纳米纤丝（CNF）与片层结构的氧化石墨烯（GO）形成的CNF-GO复合水凝胶经抗坏血酸还原制备出CNF-还原氧化石墨烯（rGO）复合水凝胶材料。通过冷冻干燥法得到CNF-rGO复合气凝胶,并进一步通过苯胺单体在CNF-rGO复合气凝胶的孔道内原位聚合制备出CNF-rGO/聚苯胺（PANI）气凝胶柔性电极复合材料。研究了不同苯胺、CNF和GO的质量比对CNF-rGO/PANI气凝胶柔性电极复合材料的结构形貌和电化学性能的影响。结果表明,苯胺原位聚合后所得CNF-rGO/PANI复合气凝胶仍具有紧密的三维多孔网络结构。与rGO/PANI气凝胶电极复合材料相比,CNF-rGO/PANI气凝胶电极复合材料具有更理想的电容行为。当CNF与GO质量比为60∶40,PANI添加量为0.1 mol时,CNF-rGO/PANI气凝胶电极复合材料比电容可达85.9 Fg-1,且其电化学性能几乎不受弯曲程度的影响,展现出了良好的柔韧性和电化学性能。      

生物质基碳气凝胶制备及应用研究

生物质材料成本低廉、碳源丰富,是碳气凝胶制备中最经济、环保和可持续性的原料。生物质基碳气凝胶展现出密度低、弹性高、比表面积大和导电性好等优异特性,有望广泛应用于电化学储能器件和吸附净化等领域。综述了生物质基碳气凝胶,如纤维素碳气凝胶、木质素基碳气凝胶、生物质衍生物基碳气凝胶以及碳气凝胶复合结构材料的制备工艺,总结了生物质基碳气凝胶在吸附和电化学等领域的应用研究。最后,分析了大规模制备结构均一和性能优良的生物质基碳气凝胶面临的机遇与挑战。     

Low-cost quasi-solid-state dye-sensitized solar cells based on a metal-free organic dye and a carbon aerogel counter electrode

Low-cost quasi-solid-state dye-sensitized solar cells (DSSCs) are designed and fabricated by using a metal-free organic dye and a mesoporous carbon aerogel instead of expensive ruthenium-based sensitizers and Pt electrode. The electrospun TiO₂ nanorods are added into a polyvinylidene fluoride (PVDF) solution to form a 3D network nanocomposite gel electrolyte. The presence of TiO₂ nanorods in the gel electrolyte obviously increases the ionic conductivity and decreases charge-transfer resistance of the DSSC. The effects of the gel electrolyte and the carbon aerogel counter electrode on electrochemical and photovoltaic properties have been investigated in detail. Particularly, an optimized DSSC with a nanocomposite gel electrolyte and a carbon aerogel counter electrode affords a power conversion efficiency (PCE) of 6.20% at a light intensity of 100 mW cm⁻².     

Dual‐Ion Electrochemical Deionization System with Binder‐Free Aerogel Electrodes

Desalination devices such as capacitive deionization (CDI) have been developed for many years as an approach to relief freshwater shortage. However, due to the limitation of physical adsorption capacity of CDI, the salt removal capacity is unable to reach high value. To enhance the desalination capacity effectively, battery materials are employed to fabricate a dual‐ion electrochemical deionization (DEDI) device. Herein, a binder‐free DEDI system with two free‐standing aerogel electrodes is reported. A Na₃V₂(PO₄)₃/graphene hybrid aerogel is used as sodium electrode and a AgCl/graphene hybrid aerogel is used as chloride electrode. With electric current passing through, sodium and chloride ions are released or absorbed by two aerogel electrodes. This system achieves super high desalination capacity, excellent cycling stability, and rapid desalination rate. The desalination capacity is as high as 107.5 mg g^?1 after 50 cycles with the current density of 100 mA g^?1. The outstanding desalination performance of this system shows a synergistic effect of combining battery materials with graphene for deionization and promises a new potential alternative of future desalination design.     

Microwave-assisted synthesis of high-loading, highly dispersed Pt/carbon aerogel catalyst for direct methanol fuel cell

A Pt supported on carbon aerogel catalyst has been synthesized by the microwave-assisted polyol process. The Pt supported on carbon aerogel catalyst was characterized by high resolution transmission electron microscopy and X-ray diffraction. The results show a uniform dispersion of spherical Pt nanoparticles 2·5–3·0 nm in diameter. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic activity of the Pt/carbon aerogel catalyst for methanol oxidation at room temperature. The Pt/carbon aerogel catalyst shows higher electrochemical catalytic activity and stability for methanol oxidation than a commercial Pt/C catalyst of the same Pt loading.