石墨烯的制备及其作为电极的典型应用

石墨烯是目前发现的唯一存在于室温条件下的二维自由态原子晶体,它具有非常优秀的电学、光学及机械性能,同时还具有非常好的热学稳定性、化学稳定性。本文主要介绍了石墨烯导电薄膜的几种主要制备方法以及石墨烯导电薄膜作为电极应用在各个领域如:液晶显示领域、光伏领域、超级电容器及LED显示器件方面的研究进展,并对石墨烯电极的制备及应用进行了展望。     

3D石墨烯/导电聚合物气凝胶复合材料在超级电容器中的研究进展

分析了近年来超级电容器电极材料尤其是3D石墨烯/导电聚合物气凝胶复合电极材料在超级电容器方面的研究进展,详细介绍了目前3D石墨烯气凝胶的制备方法,总结了3D石墨烯/导电聚合物气凝胶复合材料的不足和在存储领域的发展方向.     

石墨烯增强金属基复合材料的研究进展

石墨烯具有独特的化学、物理性能,常常被作为增强相加入金属基体中制备高强度、导电性能好、耐腐蚀等性能优异的材料。本文综述了目前石墨烯增强金属基础复合材料的制备方法、应用以及目前存在的主要问题,并对石墨烯增强基复合材料的发展进行了展望。     

石墨烯与导电高分子复合材料及其电学性能研究进展

石墨烯作为单原子厚度的二维碳原子晶体,是具有优异的力学、热学、电学性能的新型纳米复合填料。近年来,石墨烯材料在化学和物理学界引起广泛关注。论述了石墨烯与导电高分子复合材料的制备,并对其在超级电容器、太阳能电池以及电化学传感器方面的应用。     

石墨烯/导电聚合物复合防腐蚀材料制备及应用研究进展

石墨烯/导电聚合物复合材料不仅具有石墨烯优异的屏蔽性能和导电聚合物良好的氧化还原特性,还能协同发挥二者的功能,在金属防腐蚀领域有着巨大的应用潜力。本文综述了石墨烯/导电聚合物复合防腐蚀材料的制备方法,包括电化学方法、化学氧化法、分散液混合法和化学气相沉积法（CVD）;并全面总结了石墨烯/导电聚合物复合材料在防腐蚀涂层中的应用及性能。制备的石墨烯/导电聚合物复合材料可以通过电化学方法、溶剂挥发法制成石墨烯/导电聚合物防腐蚀薄膜涂层,还可以混入成膜物树脂中制备树脂复合防护涂层。讨论了石墨烯/导电聚合物在制备过程、薄膜涂层和树脂复合涂层应用中的优势与不足,提出了构建结构可控、综合性能好的复合防腐涂层是石墨烯/导电聚合物复合防腐蚀材料的未来主要发展趋势。     

多孔石墨烯材料的制备研究进展

多孔石墨烯材料结合了多孔材料与石墨烯的优点,因其比表面积大、孔结构独特、组成多样、导电性能优异等特点,逐渐成为了石墨烯材料领域的研究热点。因此,为了实现大规模合成高性能的多孔石墨烯材料,本文阐述了多孔石墨烯的制备原理并对多孔石墨烯材料的典型制备方法进行了总结,讨论了各种制备方法存在的优缺点,以及多孔石墨烯材料具备的优势与不足。基于现有的多孔石墨烯制备技术以及对未来发展需求的展望,多孔石墨烯材料的制备及调控将达到分子水平,并且将展现更加巨大的应用潜力。     

自支撑碳纳米管/石墨烯复合物柱的 制备及其电容性质

以氧化石墨和功能化碳纳米管为前驱物,采用水热法制备了自支撑碳纳米管/石墨烯复合物柱材料。利用XRD、SEM和TEM表征了样品的结构与形貌。以制备材料直接作为电极材料,无需添加导电剂和黏结剂,利用循环伏安法和恒流充放电技术研究了制备材料的电容性质。结果表明,由于碳纳米管的存在一定程度上阻止了石墨烯的重组,石墨烯/碳纳米管柱的质量比电容远高于单纯石墨烯材料。     

石墨烯/硅橡胶导电复合材料的制备及性能研究

以甲基乙烯基硅橡胶(MVQ)为主体材料、石墨烯为导电填料,制备石墨烯/MVQ导电复合材料,研究石墨烯品种和用量对复合材料物理性能和导电性能的影响。结果表明:石墨烯LKR6963的剥离程度较高、片层较薄、缺陷较少,易在硅橡胶基体中形成导电网络,提高复合材料的导电性能;随着石墨烯LKR6963用量的增大,复合材料的硬度和拉伸强度明显增大,体积电阻率逐渐减小。     

石墨烯材料在水中重金属检测中的应用

近几年,石墨烯及其复合材料的制备及应用受到广泛关注,在环境污染物检测方面取得了显著进展,尤其是水中重金属分析方法的研究。本文综述了各类石墨烯材料用于水中重金属离子检测的研究现状,着重分析了石墨烯改性电极的制备、性能及其电化学检测方法的机理和优缺点。发现石墨烯材料的优异电子传输性能,使其在重金属离子电化学测试方法开发方面具有天然优势,有助于实现在线、原位、实时检测水体中重金属离子;但是石墨烯改性电极研究刚刚起步,存在诸如抗干扰能力和选择性差、电极重复使用性能差、实际应用研究少等问题,有必要继续开展石墨烯修饰的新型复合电极制备,进一步提高电化学测试方法的选择性和抗干扰能力,增加电极使用寿命和非常规环境下的应用研究,拓展石墨烯基复合电极的应用范围等。     

氧化石墨烯与剩余活性污泥聚合制备多孔碳材料及其电化学性能

石墨烯是导电性良好的二维材料,但易重新堆叠而导致导电率和电容量下降。氧化石墨烯（GO）的生物相容性和细菌的胶体特性可使二者在水溶液中聚集为三维石墨烯基材料。将剩余活性污泥与GO悬浮液共培养形成活性污泥石墨烯水凝胶（SGH）,剩余活性污泥中的细菌可将GO还原为导电的rGO。SGH经冻干可得到具有良好亲水性和导电性的O、N自掺杂多孔材料,即活性污泥石墨烯气凝胶（SGA）。在氩气中高温退火可进一步提高材料的电化学性能。经700℃、2 h退火后的改性SGA（ANSGA）具有174 F/g的比电容值（2 A/g）,以及优异的倍率性能、离子传输性能和循环稳定性,具有进一步加工制备电极材料的应用潜力,为石墨烯基材料绿色制备和剩余活性污泥资源化利用提供方向。     

Physical and mechanical properties of poly(methyl methacrylate) -functionalized graphene/poly(vinylidine fluoride) nanocomposites: Piezoelectric β polymorph formation

Poly(methyl methacrylate) -functionalized graphene (MG) is prepared from graphene oxide (GO), using atom transfer radical polymerization (ATRP) and reducing with hydrazine hydrate. PMMA causes an increase of height of MG sheet for polymerization of MMA at side and basal planes. MG layers become thinner for exfoliation during composite formation. Graphene sheets enhance piezoelectric β-polymorph PVDF formation. MG sheets nucleate PVDF crystals and a gradual decrease of α phase occurs with a concomitant rise of β phase. Thermal stability of nanocomposites increases significantly and the T_g increase is really large (21 °C). Storage modulus shows an increase of 124%, stress at break 157% and Young’s modulus 321% for 5% MG. Parallel orientation of graphene sheets changes to random orientation for high graphene content. It exhibits conducting percolation threshold at 3.8% MG and variable range hopping model suggests that conductivity is contributed from the intergrain tunnelling and hopping between the grains.     

石墨烯电导率及其影响因素研究

采用低温扩张法对石墨插层、膨胀、剥离制备了石墨烯。采用粉末电阻率测试仪对不同条件下制得的石墨烯材料的电导率进行了测试,并对其影响机理进行了分析。结果表明,物料比例、插层时间、pH值等都对石墨烯的电导率有明显影响。     

Vertically aligned,polypyrrole encapsulated MoS2/graphene composites for high-rate LIBs anode

Ultrathin MoS₂ nanosheets were vertically anchored on the reduced graphene oxide (MoS₂/rGO) via hydrothermal method. To further engineering the surface conductivity, ultrathin polypyrrol (PPy) layer was coated on the MoS₂/rGO composite via in situ polymerization to form a bi-continuous conductive network with a sandwich-like structure. The graphene nanosheets and the PPy coating can facilitate the electrons transfer rate, while the ultrathin MoS₂ nanosheets can enhance the utilization efficiency of the active materials. The obtained MoS₂/rGO-10 composite exhibits high reversible specific capacity (970?mAh?g^?1 at 0.1?A?g^?1) and rate capability (capacity retention of 64% at 3.2?A?g^?1). Moreover, the PPy@MoS₂/rGO hybrids reveal lower specific capacity but better rate capability, and a “trade-off” effect between electrons and ions transfer resistance was observed. This easy-scalable PPy surface conductivity engineering strategy may be applied in the preparation of high-performance LIBs active materials.     

Highly conductive interconnected graphene foam based polymer composite

In this study, the impact of graphene sheet size on the electrical conductivity of interconnected graphene foam polymer composite is thoroughly investigated. Graphene oxide solution is produced from small flake graphite (SFG) (2–15 μm) and large flake graphite (LFG) (>100 μm), respectively. Each solution is used to produce three-dimensional GO foam, which is subsequently heat-treated to produce reduced graphene oxide (RGO) foam. The RGO foams are then infiltrated with poly(dimethylsiloxane) (PDMS) to produce graphene-PDMS (G-PDMS) composites. The in-plane electrical conductivity of the G-PDMS composite (0.4 wt%) from LFG reaches ∼3.2 S/m, which is more than two orders of magnitude greater than that of G-PDMS (1.9 wt%, 1.4 × 10⁻² S/m) from SFG. This value is also four orders of magnitude higher than that of the G-PDMS composite prepared from mechanical mixing of 4 wt% RGO powder made from SFG with PDMS (4.2 × 10⁻⁵ S/m). The though-plane electrical conductivity followed the same trend for SFG and LFG. This reveals that the interconnected graphene foam supplies more efficient paths for electron transfer inside the polymer than conventional graphene powder and the use of large sized graphene sheets can significantly improve the electrical properties of G-PDMS.     

Electrically conductive aluminosilicate/graphene nanocomposite

Highly electrically conductive ceramic material based on aluminosilicate/graphene nanocomposite has been prepared by high pressure (400 MPa) compaction of montmorillonite intercalated with polyaniline followed with the high temperature (1400 °C) treatment in argon atmosphere. Tablets pressed from polyaniline/montmorillonite intercalate exhibits strong texture due to the disk-shaped montmorillonite particles and, consequently, the high anisotropy in conductivity. The high temperature induced phase transformation of montmorillonite into cristobalite and mullite preserved the aluminosilicate layered structure and created good conditions for formation of graphene sheets from polyaniline layers intercalated in montmorillonite. Therefore, the texture and anisotropy in conductivity remain preserved in resulting aluminosilicate/graphene tablets, while the in-plane conductivity in aluminosilicate/graphene tablets is 23,000× higher than the conductivity of uncalcined polyaniline/montmorillonite tablets. Simple fabrication method of aluminosilicate/graphene tablets is very promising for the manufacturing of the electrically conductive and tough ceramic material, which can be exposed to corrosive environment as well as to high temperatures.     

聚对苯二甲酰癸二胺导热复合材料性能的研究

通过双螺杆挤出机制备出石墨/聚对苯二甲酰癸二胺(PA10T)和石墨烯/PA10T导热复合材料,研究了石墨和石墨烯对复合材料力学性能和导热性能的影响。研究发现:导热复合材料的拉伸强度和悬臂梁缺口冲击强度随着导热填料含量的增加呈现先增大后减小的变化,而弯曲模量和导热系数随导热填料含量的增加而增加。与石墨相比,添加更少量的石墨烯即可以显著提高复合材料的力学性能和导热性能。     

石墨烯/硅负极材料的制备及其电化学性能的研究

通过将亚微米硅与石墨烯进行原位还原复合(SG1)和机械混合(SG2)这2种方式制备了不同的石墨烯/硅复合锂离子电池负极材料。SEM结果显示,2种复合物中硅颗粒都被石墨烯片层所包夹,且分散均匀;充放电测试表明,这2种复合方式均使复合电极的首次容量损失大大减小,循环稳定性得到很大提高,其首次放电比容量分别为2 070.5mAh/g和1 534.2mAh/g,循环12次后均保持在1 000mAh/g以上;通过EIS阻抗谱对硅复合电极的导电性以及电极结构的初步研究,发现复合电极本身导电性以及材料的电接触性远优于纯硅,电极结构也相对稳定。     

Electrical behavior and positive temperature coefficient effect of graphene/polyvinylidene fluoride composites containing silver nanowires

Polyvinylidene fluoride (PVDF) composites filled with in situ thermally reduced graphene oxide (TRG) and silver nanowire (AgNW) were prepared using solution mixing followed by coagulation and thermal hot pressing. Binary TRG/PVDF nanocomposites exhibited small percolation threshold of 0.12 vol % and low electrical conductivity of approximately 10^-7 S/cm. Hybridization of TRGs with AgNWs led to a significant improvement in electrical conductivity due to their synergistic effect in conductivity. The bulk conductivity of hybrids was higher than a combined total conductivity of TRG/PVDF and AgNW/PVDF composites at the same filler loading. Furthermore, the resistivity of hybrid composites increased with increasing temperature, giving rise to a positive temperature coefficient (PTC) effect at the melting temperature of PVDF. The 0.04 vol % TRG/1 vol % AgNW/PVDF hybrid exhibited pronounced PTC behavior, rendering this composite an attractive material for making current limiting devices and temperature sensors.     

改性石墨烯对天然橡胶/丁腈橡胶复合材料热性能的影响

采用超声辅助超临界CO2方法制备石墨烯,经3-氨丙基三乙氧基硅烷(APTES)改性后,采用"预混合"的方法,得到硬脂酸/石墨烯母料。通过机械共混法制备天然橡胶(NR)/改性石墨烯(GNs)与丁腈橡胶(NBR)/GNs复合材料。通过分析复合材料的导热性能、热管理性能和压缩生热性能的变化情况,验证石墨烯的性能与硬脂酸/石墨烯"预混合"对石墨烯分散的影响。结果表明,添加3份GNs时,NRC-3、NBRC-3的导热性能分别提升了108%和194%,压缩温升降低了8. 9℃和9. 9℃。该方法制备的石墨烯导热性能优秀,硬脂酸/石墨烯的"预混合"有效改善了石墨烯在聚合物中的分散性。     

Carbon‐Polymer Composite Bipolar Plate for HT‐PEMFC

Graphene reinforced carbon‐polymer composite bipolar plate is developed using resole phenol formaldehyde resin, and conductive reinforcements (natural graphite, carbon black, and carbon fiber) using compression molding technique. Graphene is reinforced into the composite to alter various properties of the composite bipolar plate. The developed composite bipolar plate is characterized and the effect of temperature on mechanical and electrical properties is investigated with an overall aim to achieve benchmark given by US‐DOE and Plug Power Inc. The flexural strength and electrical conductivity of the composites was almost stable with the increase in temperature upto 175 °C. The composite bipolar plate maintained high in‐plane and through‐plane electrical conductivities, which is about 409.23 and 98 S cm^–1, respectively, at 175 °C. The flexural strength and shore hardness of the developed composite was around 56.42 MPa and 60, respectively, at 175 °C, and on further increase in the temperature the mechanical strengths deceases sharply. The electrical and mechanical properties of the composite bipolar plates are within the US‐DoE target. However, the various properties of the composite bipolar plate could not be sustained above 175 °C.