Preparation and supercapacitor performance of assembled graphene fiber and foam

Graphene-based materials have been full of vigor and tremendous potentiality for application in supercapacitors due to its variety of unique properties such as electronic properties, simple synthesis, etc. In developing new macroscopic nanostructured graphene materials for supercapacitors, considerable efforts have been made by the scientist including our research group. In this account, we describe our development of the construction of the assembled graphene especially fiber and foam, which have great potential in addressing the challenges in the synthesis of graphene-based electrode materials for supercapacitors. As the supercapacitors are reviewed in this article, they are accordant with the rapid development of flexible, lightweight, and wearable-electronic devices, overcoming the major some drawbacks of conventional bulk supercapacitors. We hope that this summary will benefit the further research of graphene-based materials for the applications in electrochemical energy storage devices and beyond.     

Recent advances in graphene based photoresponsive materials

Recent scientific interests reveal that graphene, with its flexibility, chemical stability, thermal conductivity,unique electronic band structure and optical transmittance, has emerged as the novel supporting material for nanocomposites for various applications. Research interests have flourished regarding decoration of conventional materials with modified graphene for achieving better optical properties. More concern is given for achieving improved photoresponse with graphene as the supporting material. The giant electron mobility and transparency of graphene enables the photo-induced electron transfer in the hybrid material, resulting in enhanced behaviour. Graphene oxide is able to effectively convert near infrared energy into heat, potentially acting as a photo-thermal switch. They act as potential candidates for photo-catalysts, sensors, photo-current switching,photo-detectors and other optical applications. In this review, we summarized the recent developments on fabrication and properties of graphene based photoresponsive materials.     

Functionalization of graphene materials by heteroatom-doping for energy conversion and storage

Recent development in nanoscience and nanotechnology has opened up new frontiers in materials science and engineering to create new materials for energy generation and storage. Owing to their earth abundance, low-cost, structural tunability, large-surface area, and unique physicochemical properties, graphitic carbon materials have attracted a great deal of attention for energy-related applications. However, the pristine graphene materials without functionalization is intractable (insoluble and infusible), which has hindered their practical applications. Therefore, considerable research effort has been devoted to the development of functionalized graphene materials with desirable properties for specific applications, including energy conversion and storage. It was demonstrated that functionalized graphene materials with tunable work functions were useful as charge-extraction materials to effectively improve solar cell performance while those with high electrocatalytic activities could be used as metal-free catalysts in fuel cells, metal-air batteries, water splitting and integrated energy systems. This article provides a timely focused review on the development of heteroatom-doped graphene materials for low-cost, but efficient, energy generation and storage.     

MXene材料储能应用研究进展

MXene是一种新型的二维过渡金属碳化物或碳氮化物,具有类似石墨烯的二维结构.MXene因其独特的物理和化学特性,以及在储能、催化、电子与光电子等领域中的良好应用前景而受到广泛关注.介绍了MXene材料的制备、表征以及在锂离子电池、钠离子电池、锂硫电池和超级电容器等储能器件上的最新研究成果.最后,对MXene材料的未来发展和挑战进行了介绍.     

功能化石墨烯的性能与应用

石墨烯是一种具有独特二维晶体结构的新型碳纳米材料,具有优异的力学、电学、光学和热学性能,但是在溶剂中难以分散限制了其在很多领域的应用.功能化石墨烯提高了分散性,充分发挥了石墨烯的优良性能,在储能、生物医药、传感器和复合材料方面具有光明的应用前景.综述了石墨烯和功能化石墨烯的制备方法、优良性能及其各领域的应用.     

纳米石墨烯的减摩抗磨研究进展

近年来,纳米石墨烯在摩擦学领域引起了一番新的热潮,纳米石墨烯因具有独特的物化性能、超薄层间结构和优良的自润滑性能,将其作为润滑添加剂能够显著提高机体的摩擦学性能。文中综述了纳米石墨烯作为固体润滑剂、水基润滑添加剂和油基润滑添加剂以及与其他纳米粒子的复合材料作为润滑添加剂的研究进展,归纳总结了石墨烯的保护层薄膜、低表面能、自润滑性能、复合材料共同作用等减摩抗磨机理;指出了纳米石墨烯存在的问题,如不同添加量的石墨烯对溶液的抗磨减摩影响较大,石墨烯的层数和结构都是影响机体抗磨减摩的重要因素,并对今后石墨烯的研究方向进行了展望。     

石墨烯基电极材料在超级电容器中的应用

随着能源消耗的日渐增长,寻找低成本、环保、寿命长的储能设备迫在眉睫。在超级电容器领域,石墨烯电极材料以其高比电容、优异倍率性能、良好导电性等优势而受到广泛关注。对石墨烯材料的制备方法、电化学性能及相关机制做了总结,目的是研究不同结构的石墨烯材料对超级电容器性能的影响,并找到性能较为优异的石墨烯基材料。最后分析了石墨烯基电极材料发展中存在的问题,并对其研究前景进行了展望。     

氧化石墨烯-单壁碳纳米管复合物的超电容性能研究

以氧化石墨烯(GO)作为表面活性剂分散原始的单壁碳纳米管(SWNT),采用超声、冷冻干燥的办法得到氧化石墨烯-单壁碳纳米管复合物,利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和电化学测试对样品的形貌、结构、组成以及电化学性质进行表征.结果表明:氧化石墨烯-单壁碳纳米管复合物电化学性质得到了显著的提高,通过调节单壁碳管与GO的比例,发现SWNT质量为GO的10%时,得到的复合材料具有最好的超电容储能特性,在6mol·L~(-1)的KOH电解液中,0.5A·g~(-1)电流密度下其比电容可达155F·g~(-1),是相同条件下GO比电容(81.5F·g~(-1))的1.9倍,这种简单的方法获得的GO-SWNT复合材料在能量存储装置方面展现了广阔的应用前景.     

Multilayered graphene membrane as an experimental platform to probe nano-confined electrosorption

Multilayered graphene membranes (MGMs) with different packing densities were prepared and used as electrodes for supercapacitors to probe nano-confined electrosorption in porous carbon materials. The electrosorption capacity of MGMs was measured against an increasing operation rate in a series of aqueous solutions of monovalent ions. The nanoconfinement effect was found prominent when the microscopic pore structure of the MGMs was controlled to be comparable to the size of hydrated ions being tested. The electrosorption capacity was found highly dependent on the type of ions. This study highlights the great potential of using easily available and structurally tunable graphene membranes as a model system to investigate fundamental problems relating to energy storage, membrane separation and nanofluidics.     

Porous graphene: Properties, preparation, and potential applications

Graphene has recently emerged as an important and exciting material.Inspired by its outstanding properties,many researchers have extensively studied graphene-related materials both experimentally and theoretically.Porous graphene is a collection of graphene-related materials with nanopores in the plane.Porous graphene exhibits properties distinct from those of graphene,and it has widespread potential applications in various fields such as gas separation,hydrogen storage,DNA sequencing,and supercapacitors.In this review,we summarize recent progress in studies of the properties,preparation,and potential applications of porous graphene,and show that porous graphene is a promising material with great potential for future development.     

Graphene-based hybrid materials and their applications in energy storage and conversion

Graphene attracts more and more scientists and researchers owing to its superior electronic,thermal,and mechanical properties.For material scientists,graphene is a kind of versatile building blocks,and considerable progress has been made in recent years.Graphene-based hybrid materials have been prepared by incorporating inorganic species and/or cross-linking of organic species through covalent and/or noncovalent interactions.The graphene-based hybrid materials show improved or excellent performance in various fields.In this review,we summarize the synthesis of graphene and graphene-based hybrid materials,and their applications in energy storage and conversion.     

Ag/graphene composite based on high-quality graphene with high electrical and mechanical properties

A simple and effective process has been reported to prepare the silver (Ag)/graphene composite with excellent mechanical and electrical properties based on high-quality graphene (HQG). The HQG was fabricated via hot pressing of reduced graphene oxide (RGO) from chemical exfoliation, while the Ag/HQG composite was obtained by using spark plasma sintering (SPS) treatment under high temperature (1500 °C) and moderate pressure (40 MPa). With low oxygen-containing functional groups and defect density, the HQG dispersed homogeneously in the composite after high-energy ball milling. In comparison to pure Ag, the as-prepared Ag/RGO composite exhibited a great enhancement of 11% electrical conductivity and 42% micro-hardness with an optimal RGO adding content (1 wt%). The Ag/HQG composite is expected to open up a new way for the novel Ag-based electrical contact materials, and further to broaden its applications in micro-electronics and switching power.     

基于超疏水表层的石墨烯电热除冰实验研究

超疏水涂层因其憎水性和优异的抗冰性能,在防除冰领域得到了广泛的关注.为研究超疏水涂层与石墨烯耦合作用的电热除冰效果,通过实验测量了石墨烯加热元件的温升速率;设计并制备用于电热除冰的加热膜构型;测量不同热流密度与环境温度下耦合组件温升情况;根据自行搭建的电热除冰实验台,研究不同热流密度对耦合组件除冰效果的影响,并与无喷涂超疏水表层加热组件的除冰能耗进行对比.实验结果表明:石墨烯加热膜比金属丝加热膜温升速率高;低温环境中耦合组件均表现出良好的温升情况;随着热流密度的不断增加,耦合组件除冰时间越短;相比传统金属丝电热组件,相同热流密度下耦合组件除冰能耗降低49％.验证主动除冰系统与超疏水涂层被动防除冰系统结合下,具有降低电热除冰能耗的可行性.     

One-step uniform growth of magnesium hydride nanoparticles on graphene

A simple solvent-free method to synthesize MgH2 nanoparticles (MgH2 NPs) uniformly grown on graphene nanosheets (GNs) has been reported in this paper. Based on the formation of MgH2 by di-n-butylmagnesium ((C4H9)2Mg) thermal decomposition under hydrogen pressure, the GNs were added as matrix to hinder the agglomeration and growing of MgH2 NPs. The fabricated MgH2/GNs nanocomposites, in which MgH2 NPs were homogenously growing in the graphene matrix, have been synthesized by the favorable adsorption energy between (C4H9)2Mg and GNs. Resulting from the one-step solvent-free route, the generated MgH2 NPs shows high hydrogen capacity and steady hydriding and dehydriding properties, without the interference of the synthetic medium. At the same time, the size of the fabricated MgH2 NPs can be controlled by adjusting the mass ratio of MgH2 to graphene, the various hydrogen pressure and temperature. Attributed to smaller size effect, well uniform distribution of high density MgH2 NPs, and the agglomeration blocking ability of graphene, the MgH2/GNs-40 wt% exhibits the favorite hydrogen storage performance.     

An equivalent 1D nanochannel model to describe ion transport in multilayered graphene membranes

Multilayered graphene-based membranes are promising for a variety of applications related to ion or molecule transport, such as energy storage and water treatment. However, the complex three-dimensional cascading nanoslit-like structure embedded in the membrane makes it difficult to interpret and rationalize experimental results, quantitatively compare with the traditional membrane systems, and quantitatively design new membrane structures. In this paper, systematic numerical simulations were performed to establish an equivalent onedimensional(1 D) nanochannel model to represent the structure of multilayered graphene membranes. We have established a quantitative relationship between effective diffusion length Leffand cross-section area Aeffof the1 D model and our recently developed two dimensional(2 D) representative microstructure for graphene membranes. We find that only in the cases of a relatively large lateral size L( ~100 nm) and a small slit size h( 2 nm), the effective diffusion length Leffand Aeffcan be calculated by an over-simplified but often used model. Otherwise, they show complex dependence on all three structural parameters of the 2 D structural model.Our equivalent 1 D nano-channel model can reproduce experimental results very well except for h 0.5 nm. The discrepancy could be attributed to the anomalous behaviour of molecules under nano-confinement that is not considered in our simulations. This model can also be extended to multilayered membranes assembled by other2 D materials.     

基于石墨烯材料的pH传感器的研究进展

石墨烯材料因其独特的性质,在电化学检测领域备受关注。介绍了近年来石墨烯材料在pH传感器中的研究进展,主要成果包括石墨烯pH电极、液栅型石墨烯场效应管(SGFET)pH传感器以及顶栅型石墨烯场效应管pH传感器。     

二维功能材料的生物学效应

继石墨烯被发现以来,因其稳定的二维结构和独特的物理化学性质,在材料、能源、环境、生物等领域展现出广泛应用前景,也已成为纳米生物医学的研究热点,被用于生物传感、细胞成像、药物运输、组织工程等领域.随后,具有类似结构的相关二维功能材料的研究也层出不穷、备受关注.本文综述了以石墨烯为代表的二维功能材料的生物学效应,并作出展望.     

A review on hybridization modification of graphene and its polymer nanocomposites

Recently,graphene has attracted numerous interests from both fundamental and applied fields due to its excellent mechanical,thermal,electrical conductivity and other novel properties.This review gives an overview of recent progress on hybridization modifications of graphene with carbon nanomaterials.Some example applications of graphene-based nanohybrids in polymer composites,optical and conducting materials,high performance electrolyte materials and as well as other functional materials are summarized and discussed.     

石墨烯的制备研究进展

石墨烯是一种二维六边形结构的碳质新材料,因为其优异性能而成为近几年的研究热点.主要介绍了两种石墨烯的常用制备方法:微机械剥离法和化学方法,同时分析了各种方法的优缺点,并对未来的制备方法作了展望.     

高响应率石墨烯-CsPbBr3量子点光电探测器

全无机金属卤化物钙钛矿材料CsPbX_3(X=Cl,Br,I)不仅有优异光电特性,还有比有机-无机杂化钙钛矿更好的热稳定性,在光电探测器领域有很大应用前景.但由于全无机钙钛矿材料自身迁移率较低,直接用于光电探测器其光响应率也很低,难以满足实际应用.以热注入法合成高质量的CsPbBr_3钙钛矿量子点材料,再将其与高迁移率的单层石墨烯薄膜相结合,构建出石墨烯-CsPbBr_3量子点复合光电探测器,光响应率高达3.5×10~4 A·W~(-1).研究表明引入石墨烯材料作为传输层后,CsPbBr_3量子点的光生电子空穴对得到有效分离并快速传输.两种材料界面处存在陷阱态,产生了光栅压效应,延长了载流子寿命.两种机制结合使复合光电探测器的光响应率大大提升.