摘要
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。
Hydrogen energy is one of the most important choices for realizing clean energy because of its wide sources,no pollution,and high energy density.The technological innovation of fuel cells contributes to the attractive prospect of hydrogen energy in vehicles,but the problem of hydrogen filling and hydrogen storage has become one of the obstacles to the development of hydrogen energy cars.The safe and efficient hydrogen storage is crucial for the large-scale application of hydrogen energy.Till now there have been developed three main hydrogen storage methods,which include high-pressure gaseous hydrogen storage,low-temperature liquid hydrogen storage and solid-state hydrogen storage.The gravimetric density of gaseous hydrogen storage system can be promoted by increasing the pressure of hydrogen and the specific strength of container material.However,H2 molecular interaction causes a relatively low volumetric density of gaseous hydrogen storage system,and excessively high hydrogen pressure challenges the safety and heightens design difficulty and cost of hydrogen tanks.The liquid hydrogen storage owns ideal gravimetric and volumetric density,which can be realized by compressing and liquefying hydrogen gas.However,liquid hydrogen is particularly prone to volatilize and liquid hydrogen container requires strict storing conditions.In addition,the liquefying process of gaseous hydrogen is uneconomical,as it consumes an energy quantity that constitutes about 40%of the combustion heat release of the stored hydrogen.For the solid-state hydrogen storage,hydrogen is stored in the hydrides in the form of atom or ion.Hence,the solid-state hydrogen storage obtains an impressively high volumetric density and enjoys greater security because the hydrogen storage materials absorb/desorb hydrogen at mild conditions.But the gravimetric density of hydrogen storage materials is comparatively low.The high-pressure hybrid hydrogen storage vessel,which combines the advantages of gaseous and solid-state hydrogen storage methods,offers a feasible path to safe and high-density hydrogen storage.The volumetric density of high-pressure hydrogen tank can be effectively enhanced by the hydrogen storage materials,resulting in lower operating pressure,smaller volume,and higher safety.The performance promotion of the high-pressure hybrid hydrogen storage vessels depends upon the development of materials with excellent hydrogen sorption performances under high hydrogen pressure.The AB2 type ZrFe2-based and TiCr2 based alloys are the currently prevailing high-pressure hydrogen storage materials.Though researchers mainly concentrate on and have achieved the regulation of storage capacity,absorption/desorption pressure plateau and kinetics through the alloying trials which partially substitute elements with various atomic radius and electronic structures for either A-site or B-site,the gravimetric densities of ZrFe2-based and TiCr2-based alloys are still unsatisfactory.NaAlH 4 and AlH 3 display considerable potential as candidate storage materials owing to their intrinsically high storage density.For NaAlH 4,sufficient works have preliminarily confirmed the effectiveness of nanosizing and catalyst-doping toward dehydrogenation temperature reduction and cyclic stability enhancement.And the yield of AlH 3 along with its crystallinity can likely be enhanced by adopting ball milling or improving the solvent.This review starts with a brief introduction of how the high-pressure hybrid hydrogen storage vessel works and a summary of the performance requirements of the hydrogen storage materials.It then provides detailed discussion and description upon the structure,characteristics and research status quo with respect to the above-mentioned two species of high-pressure hydrogen storage materials,i.e.hydrogen storage alloys(ZrFe2,TiCr2)and aluminum based complex hydrides(NaAlH4,AlH3).
作者
周超
王辉
欧阳柳章
朱敏
ZHOU Chao;WANG Hui;OUYANG Liuzhang;ZHU Min(Key Laboratory of Advanced Energy Storage Materials of Guangdong Province,School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641;China-Australia Joint Laboratory for Energy & Environmental Materials,South China University of Technology,Guangzhou 510641)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第1期117-126,共10页
Materials Reports
基金
国家自然科学基金创新群体项目(51621001)
国家自然科学基金联合基金项目(U1601212)~~
关键词
固态储氢
高压复合储氢罐
高压储氢材料
ZrFe2
TiCr2
solid-state hydrogen storage
high-pressure hybrid hydrogen storage vessel
high-pressure hydrogen storage material
ZrFe2
TiCr2
