高容量储氢材料的研究进展

氢能是一种理想的二次能源.氢能开发和利用需要解决氢的制取、储存和利用3个问题,而氢的规模储运是现阶段氢能应用的瓶颈.氢的储存方法有高压气态储存、低温液态储存和固态储存等3种.固态储氢材料储氢是通过化学反应或物理吸附将氢气储存于固态材料中,其能量密度高且安全性好,被认为是最有发展前景的一种氖气储存方式.由轻元素构成的轻质高容量储氢材料,如硼氢化物、铝氢化物、氨摹氢化物等,理论储氢容量均达到5%(质量分数)以上,这为固态储氢材料与技术的突破带来了希望.新型储氢材料未来研究的重点将集中于高储氢容量、近室温操作、可控吸/放氢、长寿命的轻金属基氢化物材料与体系.     

一种新型储氢材料——纳米炭纤维的制备及其储氢的研究

氢能是理想的清洁能源之一,已引起人们广泛的重视。为了充分利用氢能使用的分散性及不连续性等优点,必须解决氢的储存及运输问题,储氢材料则可能是可供选择的最佳方法。储氢材料的研究是氢能利用的关键技术,具有高储氢容量的纳米炭纤维的研究将促进氢能的发展。 本项目以具有高储氢能力的纳米炭纤维的制备和储氢特性研究为目标,利用气相流动催化法和高压容积法对纳米炭纤维     

储氢技术及其关键材料研究进展

氢能是未来能源结构中最具发展潜力的能源载体,氢的廉价制备、安全高效储送以及大规模应用是当今研究的重点,而氢能的储存是其中的关键性问题.本文综述了目前主要的储氢技术和储氢材料,如高压气态储氢、低温液态储氢、合金储氢、有机液体氢化物储氢、碳质材料储氢和金属有机骨架类聚合物储氢等,并对未来的研究方向进行了展望.     

储氢材料的研究进展

氢能源以其可再生性和良好的环保效应成为未来最具发展潜力的能源载体,氢能被公认为人类未来的理想能源,而氢的储存是发展氢能技术的难点之一.本文综述了目前主要的储氢材料,如合金储氢、配位氢化物储氢、碳质材料储氢、有机液体氢化物储氢,并对未来的储氢材料发展进行了展望.     

高密度储氢材料研究进展

氢是一种清洁的燃料,氢能是未来有发展前景的新型能源之一.氢的储存是氢能现阶段开发和利用的瓶颈.氢的储存方法有高压气态储存、低温液态储存和固态储存等3种,其中高压气态储存或低温液态储存不能满足将来的储氢目标.固态储氢是通过化学或物理吸附将氢气储存于固态材料中,其能量密度高且安全性好,被认为是最有发展前景的一种氢气储存方式.高密度储氢材料由轻元素构成,包括铝氢化物、硼氢化物、氨基氢化物、氨硼烷等,理论储氢质量分数均达到5%以上.综述了高密度储氢材料的研究进展,认为高储氢容量、近室温操作、可控吸/放氢、长寿命的轻质氢化物材料有希望达到燃料电池和移动氢源应用的目标.     

PEMFC备用氢能发电站的储氢问题探讨

在介绍目前国内外各种成熟的工业储氢方法,并指出储氢技术研究热点和发展方向的基础上,针对人防工程备用氢能发电站的技术要求,对各种适用的储氢方式进行了比较,探讨了人防工程备用氢能发电站的氢气储存方法,以及氢气安全储存、运输与监控、反应热处理等问题。     

一维碳纳米材料储氢机理及应用前景

氢能的储存是氢能利用的关键，一维碳纳米材料具有非常高的比表面积及一些常规材料所不具备的特异效应和性能，有望成为颇具优势的储氢材料。通过简述一维碳纳米材料储氢在各国的研究成果，表明其储氢容量比现有的一般储氢技术高1至2个数量级，引起世人的瞩目；详细介绍了碳纳米纤维的储氢机理，可能包括氢的物理和化学吸附两种形式，详细情况尚待深入研究；除此以外，还有许多诸如：如何提高体积储氢密度和氢的吸脱附速度及动力学和实用条件下的吸放氢研究等问题需要解决。     

储氢材料发展现状

氢能作为一种清洁、高效、安全、可持续的新能源。被视为21世纪最具发展潜力的清洁能源，氢的存储是目前制约氢能发展的关键因素之一。本文主要介绍了储氢合金、碳质储氢材料、络合物储氢材料、改性四氧化三铁储氢材料等数种储氢材料的发展现状，简单介绍其储氢机理和应用前景。     

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。     

高压复合储氢罐用储氢材料的研究进展

氢能因来源广、无污染、热值高等特点成为解决能源问题的重要方案。随着燃料电池技术的发展,氢能在车载方面的应用得到进一步拓宽,但氢气的加注、存储问题成为限制氢能汽车发展的瓶颈之一。实现氢气安全高效的存储是氢能规模化应用的关键。目前主要的储氢方式有高压气态、低温液态、固态。通过增加氢气压力和提高容器材料的比强度,可有效提高气态储氢系统的质量储氢密度,但由于气体分子间作用力的影响,高压气态储氢的体积储氢密度较低。同时过高的氢压对安全储氢罐的设计和成本也是一大挑战。通过加压、降温液化氢气实现的液态储氢拥有理想的质量储氢密度和体积储氢密度,但保存液态氢对设备要求十分苛刻,且液化氢气所需能耗为氢燃烧热值的40%,得不偿失。固态储氢方式将氢以原子、离子的形式存储于氢化物中,因此固态储氢材料的体积储氢密度可观,且材料吸/放氢条件温和,安全性高,但固态储氢材料的质量储氢密度不占优势。高压复合储氢罐将高压储氢技术与固态储氢材料相结合,同时拥有气态储氢与固态储氢的优势,是实现安全高密度储氢的有效途径。通过气-固复合的储氢方式,可有效提升高压储氢罐的体积储氢密度,减小储氢罐体积,降低充氢压力,提高安全性。而发展在高压条件下具有良好充/放氢特性的储氢材料是提升高压复合储氢罐性能的关键。TiCr2基、ZrFe2基AB2型合金是主要的高压储氢合金,对它们的研究集中在通过利用不同原子半径、电子结构的合金元素进行A侧和/或B侧元素替代,实现对合金平台压、容量、吸放氢动力学性能的有效调控。但TiCr2基、ZrFe2基储氢合金的质量储氢密度仍然偏低,相比之下,NaAlH4与AlH3具有高的储氢密度,是潜在的高压储氢材料。通过纳米化、掺杂催化剂等手段能够有效降低NaAlH4的脱氢温度,提高其循环稳定性;通过球磨、改善溶剂等方法可提升AlH3的合成产率、改善其结晶性。本文简要介绍了高压复合储氢罐的原理及对高压储氢材料的主要性能要求,着重评述了间隙型储氢合金(TiCr2、ZrFe2)、铝基金属氢化物(NaAlH4、AlH3)两类高压储氢材料的结构、性能特点及研究进展。     

NaAlH4空间约束体系的构建及其脱/加氢行为

配位氢化物具有较高的质量储氢密度,已成为国内外储氢材料的研究热点,但尚未解决的脱/加氢温度过高、速率慢和可逆性差等问题是制约其实际应用的主要原因.利用孔性材料的结构特点来构建纳米尺度的空间约束体系,可有效地改善配位氢化物的脱/加氢性能.以NaAlH4为例,介绍了孔性材料的制备和表面修饰,分析了配位氢化物/孔性介质空间约束体系的构建及其且兑/加氢行为.这种空间约束体系为改善配位氢化物的储氢性能提供了一条新途径.进一步构建配位氢化物/孔性介质/催化剂的空间约束体系,实现对配位氢化物的复合催化,将是今后努力的方向.     

Improving the Hydrogen Reaction Kinetics of Complex Hydrides

Alanates, borohydrides, and amides are complex hydrides with high concentration hydrogen that have been actively investigated for materials‐based hydrogen storage on‐board polymer electrolyte membrane fuel cell (PEMFC) vehicle applications. The major challenge is to release hydrogen at fuel cell working temperature range at fast enough rate without simultaneous desorption of fuel cell poisoning impurities. We review recent progress in hydrogen reaction mechanism and schemes for complex hydride hydrogen storage.     

Complex Hydrides for Energy Storage,Conversion, and Utilization

Functional materials are the key enabling factor in the development of clean energy technologies. Materials of particular interest, which are reviewed herein, are a class of hydrogenous compound having the general formula of M(XH_n)_m, where M is usually a metal cation and X can be Al, B, C, N, O, transition metal (TM), or a mixture of them, which sets up an iono‐covalent or covalent bonding with H. M(XH_n)_m is generally termed as a complex hydride by the hydrogen storage community. The rich chemistry between H and B/C/N/O/Al/TM allows complex hydrides of diverse composition and electronic configuration, and thus tunable physical and chemical properties, for applications in hydrogen storage, thermal energy storage, ion conduction in electrochemical devices, and catalysis in fuel processing. The recent progress is reviewed here and strategic approaches for the design and optimization of complex hydrides for the abovementioned applications are highlighted.     

Nanoporous Polymers for Hydrogen Storage

The design of hydrogen storage materials is one of the principal challenges that must be met before the development of a hydrogen economy. While hydrogen has a large specific energy, its volumetric energy density is so low as to require development of materials that can store and release it when needed. While much of the research on hydrogen storage focuses on metal hydrides, these materials are currently limited by slow kinetics and energy inefficiency. Nanostructured materials with high surface areas are actively being developed as another option. These materials avoid some of the kinetic and thermodynamic drawbacks of metal hydrides and other reactive methods of storing hydrogen. In this work, progress towards hydrogen storage with nanoporous materials in general and porous organic polymers in particular is critically reviewed. Mechanisms of formation for crosslinked polymers, hypercrosslinked polymers, polymers of intrinsic microporosity, and covalent organic frameworks are discussed. Strategies for controlling hydrogen storage capacity and adsorption enthalpy via manipulation of surface area, pore size, and pore volume are discussed in detail.

     

Recent advances and remaining challenges of nanostructured materials for hydrogen storage applications

The rapid and extensive development of advanced nanostructures and nanotechnologies has driven a correspondingly rapid growth of research that presents enormous potential for fulfilling the practical requirements of solid state hydrogen storage applications. This article reviews the most recent progress in the development of nanostructured materials for hydrogen storage technology, demonstrating that nanostructures provide a pronounced benefit to applications involving molecular hydrogen storage, chemical hydrogen storage, and as supports for the nanoconfinement of various hydrides. To further optimize hydrogen storage performance, we emphasize the desirability of exploring and developing nanoporous materials with ultrahigh surface areas and the advantageous incorporation of metals and functionalities, nanostructured hydrides with excellent mechanic stabilities and rigid main construction, and nanostructured supports comprised of lightweight components and enhanced hydride loading capacities. In addition to highlighting the conspicuous advantages of nanostructured materials in the field of hydrogen storage, we also discuss the remaining challenges and the directions of emerging research for these materials.     

Hydrogen Storage of Magnesium-Based Nanocomposites System

Hydrogen storage in traditional metallic hydrides can deliver about 1.5 to 2.0 wt pct hydrogen but magnesium hydrides can achieve more than 7 wt pct. However, these systems suffer from high temperature release drawback and chemical instability problems. Recently, big improvements of reducing temperature and increasing kinetics of hydrogenation have been made in nanostructured Mg-based composites. This paper aims to provide an overview of the science and engineering of Mg materials and their nanosized composites with nanostructured carbon for hydrogen storage. The needs in research including preparation of the materials, processing and characterisation and basic mechanisms will be explored. The preliminary experimental results indicated a promising future for chemically stable hydrogen storage using carbon nanotubes modified metal hydrides under lower temperatures.     

轻质金属-铝氢化物贮氢材料的研究进展

介绍了几种轻质金属-铝氢化物贮氢材料的吸放氢机理和研究进展.轻质金属-铝氢化物贮氢密度高,但存在动力学性能差、放氢温度高、可逆反应程度低等缺点,目前主要通过掺杂催化剂、降低材料的颗粒尺寸等方法来创提高吸放氢的速率和效率.随着研究的深入,轻质金属-铝氢化物在贮氢方面将有广阔的发展前景.     

Metal Hydride Nanoparticles with Ultrahigh Structural Stability and Hydrogen Storage Activity Derived from Microencapsulated Nanoconfinement

Metal hydrides (MHs) have recently been designed for hydrogen sensors, switchable mirrors, rechargeable batteries, and other energy‐storage and conversion‐related applications. The demands of MHs, particular fast hydrogen absorption/desorption kinetics, have brought their sizes to nanoscale. However, the nanostructured MHs generally suffer from surface passivation and low aggregation‐resisting structural stability upon absorption/desorption. This study reports a novel strategy named microencapsulated nanoconfinement to realize local synthesis of nano‐MHs, which possess ultrahigh structural stability and superior desorption kinetics. Monodispersed Mg₂NiH₄ single crystal nanoparticles (NPs) are in situ encapsulated on the surface of graphene sheets (GS) through facile gas–solid reactions. This well‐defined MgO coating layer with a thickness of ≈3 nm efficiently separates the NPs from each other to prevent aggregation during hydrogen absorption/desorption cycles, leading to excellent thermal and mechanical stability. More interestingly, the MgO layer shows superior gas‐selective permeability to prevent further oxidation of Mg₂NiH₄ meanwhile accessible for hydrogen absorption/desorption. As a result, an extremely low activation energy (31.2 kJ mol^–1) for the dehydrogenation reaction is achieved. This study provides alternative insights into designing nanosized MHs with both excellent hydrogen storage activity and thermal/mechanical stability exempting surface modification by agents.