新型纳米结构炭材料的储氢研究

氢能是一种清洁的可再生能源。由于传统的储氢材料和储氢技术达不到氢燃料电池电动车的实用要求,储氢问题已成为氢能应用中最急需解决的关键问题。近年来,各种新型纳米结构炭材料的储氢已成为国际上的一个研究热点,引起了人们的广泛关注。但在这一研究领域中一直存在着许多争议和很大的分歧。通过综述国内外近几年来各种新型纳米结构炭材料如单壁碳纳米管、多壁碳纳米管、石墨纳米纤维以及炭纳米纤维等的储氢研究进展,指出了这一领域中需要解决的问题如储氢测试方法的标准化、纳米结构炭材料的评价以及储氢机制和吸附位的研究等。     

结构储电碳纤维复合材料研究进展

复合材料化是航空、航天、国防、交通等装备结构升级的重要趋势。碳纤维复合材料的力学性能优异,同时兼具良好的导电特性,可用于存储和释放电能,实现结构的承载和储/放电一体化,从而达到材料多功能化和结构轻量化。结构储电复合材料通常是采用碳纤维织物作为电极材料,采用具有结构承载和离子导电的多功能聚合物基体为固态电解质,玻璃纤维织物等作为隔膜材料。本文主要对典型结构储电复合材料进行综述,包括结构电池、结构介电电容器和结构超级电容器,详细阐述了三种结构储电复合材料的组分材料、器件工作原理及多功能特性等。通过对比三种结构储电复合材料,概括了结构储电复合材料所面临的问题和挑战,提出了结构储电复合材料的发展趋势。      

电化学电容器复合电极材料铜氧化物/多孔炭的制备及电化学性

通过化学沉积法制备了金属铜氧化物/多孔炭复合电极材料,考察了热处理温度及金属铜氧化物负载量对其理化性能的影响.测试结果表明,热处理过程能有效改变铜氧化物的形态,而铜氧化物的形态影响着复合电极材料的电化学行为.当多孔炭电极负载20wt%铜氧化物时,其循环伏安曲线出现较强的峰值电流,但其电化学性能不稳定,这种情况随着负载量的减少而有所改善.当负载3wt%金属铜氧化物时,其单电极比电容达到325F/g,高于空白多孔炭的比电容（256F/g）.     

玉米芯活性炭的制备及其电化学性能研究

以玉米芯为原料,采用KOH活化法制备超级电容器用活性炭。利用低温氮气吸附及恒流充放电、循环伏安、交流阻抗等方法测定活性炭的孔结构及其用作电极材料的电化学性能。研究了脱灰对玉米芯活性炭孔结构及其电化学性能的影响。结果表明,在碱炭比3∶1、活化温度为800℃、活化时间为1h的条件下,可以制备出比表面积为2019m2/g、总孔容为1.084cm3/g、中孔率为15.6%的高比表面积活性炭。玉米芯经脱灰处理可以显著改善其所制活性炭的孔隙发达程度和中孔分布,脱灰玉米芯活性炭的比表面积、总孔容及中孔率分别可达2311 m2/g、1.246cm3/g和26.0%。玉米芯活性炭电极材料在3mol/L KOH的电解液中具有良好的电化学性能,其比电容量可达253F/g。脱灰玉米芯活性炭电极的比电容量更高(可达278F/g),比电容提高9.9%,且内阻更小。     

Single‐Crystalline,Metallic TiC Nanowires for Highly Robust and Wide‐Temperature Electrochemical Energy Storage

Customized electrode materials with good temperature adaptability and high‐rate capability are critical to the development of wide‐temperature power sources. Herein, high‐quality TiC nanowires are uniformly grown on flexible carbon cloth as free‐standing electric‐double‐layer supercapacitor electrode. The TiC nanowires, 20–40 nm wide and 3–6 µm long, are single‐crystalline and highly conductive that is close to typical metal. Symmetric supercapacitors are constructed with ionic liquid electrolyte and TiC nanowires electrodes as wide‐temperature and long‐cycle stable power source. Ultrastable high‐rate cycling life of TiC nanowire arrays electrodes is demonstrated with capacitance retention of 96.8% at 60 °C (≈440 F g^?1), 99% at 25 °C (≈400 F g^?1), and 98% at ?25 °C (≈240 F g^?1) after 50 000 cycles at 10 A g^?1. Moreover, due to high electrical conductivity, the TiC nanowire arrays show ultrafast energy release with a fast response time constant of ≈0.7 ms. The results demonstrate the viability of metal carbide nanostructures as wide‐temperature, robust electrode materials for high‐rate and ultrastable supercapacitors.     

Conductive Carbon Nitride for Excellent Energy Storage

Conductive carbon nitride, as a hypothetical carbon material demonstrating high nitrogen doping, high electrical conductivity, and high surface area, has not been fabricated. A major challenge towards its fabrication is that high conductivity requires high temperature synthesis, but the high temperature eliminates nitrogen from carbon. Different from conventional methods, a facile preparation of conductive carbon nitride from novel thermal decomposition of nickel hydrogencyanamide in a confined space is reported. New developed nickel hydrogencyanamide is a unique precursor which provides self‐grown fragments of ?N?C?N? or N?C? C?N and conductive carbon (C‐sp²) catalyst of Ni metal during the decomposition. The final product is a tubular structure of rich mesoporous and microporous few‐layer carbon with extraordinarily high N doping level (≈15 at%) and high extent of sp² carbon (≈65%) favoring a high conductivity (>2 S cm^?1); the ultrahigh contents of nongraphitic nitrogen, redox active pyridinic N (9 at%), and pyrrolic N (5 at%), are stabilized by forming Ni? N bonds. The conductive carbon nitride harvests a large capacitance of 372 F g^?1 with >90% initial capacitance after 10 000 cycles as a supercapacitor electrode, far exceeding the activated carbon electrodes that have <250 F g^?1.     

Influence of the synthesis method on electrical storage capacity of graphene-related materials

ABSTRACT

The electrochemical properties and their relationship with the physico-chemical properties of graphene-based materials have been studied. Graphite was used as the raw material and it was oxidised and then reduced by two alternative approaches, namely thermal and multi-step reduction using ascorbic acid. It was demonstrated that the physico-chemical characteristics of the material are directly related to the synthesis method and greatly influence the major capacitance of the material. It was observed that the materials with lower levels of functional oxygen groups and with a more ordered structure, i.e. similar to graphene powder, are the ideal candidates for use in electrochemical applications as these materials have better capacitance and specific capacitances.     

超级电容器电极材料

本文综述了碳基材料、金属氧化物及水合物材料和导电聚合物材料作为超级电容器电极材料的最新研究进展。     

Recent Progress in Some Amorphous Materials for Supercapacitors

A breakthrough in technologies having “green” and sustainable energy storage conversion is urgent, and supercapacitors play a crucial role in this area of research. Owing to their unique porous structure, amorphous materials are considered one of the best active materials for high‐performance supercapacitors due to their high specific capacity, excellent cycling stability, and fast charging rate. This Review summarizes the synthesis of amorphous materials (transition metal oxides, carbon‐based materials, transition metal sulfides, phosphates, hydroxides, and their complexes) to highlight their electrochemical performance in supercapacitors.     

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.     

Carbon nanomaterials for advanced energy conversion and storage

It is estimated that the world will need to double its energy supply by 2050. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. Comparing to conventional energy materials, carbon nanomaterials possess unique size-/surface-dependent (e.g., morphological, electrical, optical, and mechanical) properties useful for enhancing the energy-conversion and storage performances. During the past 25 years or so, therefore, considerable efforts have been made to utilize the unique properties of carbon nanomaterials, including fullerenes, carbon nanotubes, and graphene, as energy materials, and tremendous progress has been achieved in developing high-performance energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries) devices. This article reviews progress in the research and development of carbon nanomaterials during the past twenty years or so for advanced energy conversion and storage, along with some discussions on challenges and perspectives in this exciting field.     

Nanostructured materials for microwave receptors

Microwave heating promises numerous benefits over conventional heating including rapid thermal ramps, energy transfer rather than heat transfer, material selectivity, and improved automation and safety. This set of advantages has led to growing application in industrial processes. Currently, use of microwave heating is restricted because many materials of interest have poor dielectric loss properties and therefore respond poorly to microwave radiation. For this reason, nanostructured materials with high dielectric loss constants that can absorb microwave energy and convert it to heat are desired. Combination of the nanoscale receptors with base materials offers the opportunity to create composites with a high dielectric loss factor. This review covers the development of nanostructured microwave receptors and their applications. The structure of microwave receptors and their compatibility with the base material have a significant effect on the final dielectric properties. Therefore, various nanostructured microwave receptors, their surface modification, and the effect of the interface between the nanostructured receptors and the base materials are reviewed. Fundamental aspects of dielectric materials and their role in dielectric performance are discussed. Finally, key challenges, directions for further studies, and some promising nanostructured microwave receptors are suggested.     

电化学超级电容器电极材料的研究进展

电化学超级电容器以其独特的大容量、大电流快速充放电和高的循环使用寿命等特点,受到世人的青睐,致使许多新型的电化学超级电容器电极材料相继被发现和应用.为进一步促进电化学超级电容器的发展,在综述了近年来出现的各种电化学超级电容器电极材料的基础上,提出按材料种类将其分为四大系列:碳材料系列、过渡金属氧化物系列、有机导电聚合物系列和其他系列.并就其各自的特点和性能进行了分析比较,得出了碳材料系列主要向高比表面积和可控微孔孔径方向发展和过渡金属氧化物系列主要向提高材料本身的利用率方向发展以及导电聚合物系列主要向无机、有机杂化方向发展的结论.     

利用核桃壳制备高比表面积活性炭电极材料的研究

以核桃壳为原料,采用KOH活化法制备活性炭,并将其用作超级电容器电极材料。利用N2吸附和扫描电镜(SEM)表征活性炭的孔结构及表面形貌,系统研究碱炭比(KOH与核桃壳炭化料的质量比)对活性炭孔结构的影响,并采用恒流充放电及循环伏安等测定核桃壳活性炭电极材料在3mol/L KOH电解液中的电化学性能。结果表明,随着碱炭比的增大,活性炭的比表面积、总孔容及中孔比例先逐渐增大后稍有减小。当活化温度为800℃,活化时间为1h,碱炭比为4时,可制备出比表面积为2404m2/g,总孔容为1.344cm3/g,中孔比例为28.6%,孔径分布在0.7~3.0nm之间的高比表面积活性炭。该活性炭用作超级电容器电极材料具有良好的大电流放电特性和优异的循环性能,电流密度由50mA/g提高到5000mA/g时,其比电容由340F/g降低到288F/g,经1000次循环后,比电容保持率为93.4%。     

废茶叶基活性炭的制备及其电化学性能研究

以废茶叶的炭化料为前驱体,KOH为活化剂(碱炭比1∶1、2∶1、3∶1),在800℃下活化1h制备双电层电容器用活性炭电极材料。利用扫描电镜、低温N2吸附对活性炭的形貌、孔结构进行表征,采用恒流充放电、循环伏安和交流阻抗等测试方法评价其在3mol/L KOH电解液中的电化学性能。结果表明,3种活性炭比表面积、总孔容和中孔率最高分别达1 900m2/g、0.919 4cm3/g和35.7%;3种活性炭电极材料在0.055 6 A/g电流密度下的比电容分别为202F/g、255F/g、194F/g,电流密度增加到2.780A/g时,电容保持率分别为84.2%、67.1%、86.6%;等效串联电阻仅为0.10~0.12Ω;在碱碳比为2∶1时制备的活性炭电极材料在2.363A/g下比电容为148F/g,经1 000次循环充放电后,其质量比电容为147.7F/g,电容保持率高达99.3%。     

三羟甲基氨基甲烷/蒙脱土纳米复合贮能材料研究

研究了三羟甲基氨基甲烷 (TAM ) /蒙脱土复合贮能材料的制备方法。用XRD、IR、DSC等方法对其结构及贮能性能进行了分析 ,结果表明 :该材料是一种纳米复合贮能材料 ,不仅具有较高的相转变焓 ,且塑晶失重现象较弱 ,具有良好的使用性能。     

High‐Performance Asymmetric Supercapacitors Based on Multilayer MnO2/Graphene Oxide Nanoflakes and Hierarchical Porous Carbon with Enhanced Cycling Stability

In this work, MnO₂/GO (graphene oxide) composites with novel multilayer nanoflake structure, and a carbon material derived from Artemia cyst shell with genetic 3D hierarchical porous structure (HPC), are prepared. An asymmetric supercapacitor has been fabricated using MnO₂/GO as positive electrode and HPC as negative electrode material. Because of their unique structures, both MnO₂/GO composites and HPC exhibit excellent electrochemical performances. The optimized asymmetric supercapacitor could be cycled reversibly in the high voltage range of 0–2 V in aqueous electrolyte, which exhibits maximum energy density of 46.7 Wh kg^?1 at a power density of 100 W kg^?1 and remains 18.9 Wh kg^?1 at 2000 W kg^?1. Additionally, such device also shows superior long cycle life along with ～100% capacitance retention after 1000 cycles and ～93% after 4000 cycles.