阴极支撑Ni-YSZ/YSZ/LSM-YSZ固体氧化物电解池制氢性能研究

利用固体氧化物电解池(Solid oxide electrolysis cell,SOEC)在高温下电解水蒸气制氢,被认为是未来的大规模制氢方法之一.本文采用干压法和丝网印刷法制备了SOEC,考察了氢电极气氛和工作温度对SOEC电解性能的影响,测试了SOEC的稳定性.实验结果表明:氢电极进气中适宜的水蒸气含量为70%～80%;电解池在800,850和900℃,1.50 V的产氢速率分别为89,163和243 N·ml·cm-2·h-1;在900℃以0.33 A·cm-2恒流电解2 h,电解电压的稳定值为0.98 V,并且电解池运行稳定,无明显衰减.阻抗谱解析表明,电极过程是整个电解池电极反应的速度控制步骤.     

高温固体氧化物电解池钙钛矿型氧电极材料Ba_xSr_(1-x)Co_(0.8)Fe_(0.2)O_(3-δ)结构计算与性能研究

研究和开发高性能的钙钛矿型混合电导氧化物是目前高温固体氧化物电解池(SOEC)氧电极材料研究的热点.选择BaxSr1-xCo0.8Fe0.2O3-δ系列材料,通过对材料的容差因子、关口半径、晶格自由体积等计算,以及对平均键能、B位离子的变价能力、催化活性等方面的分析,确定了A位最佳配比.对优化出的Ba0.5Sr0.5Co0.8Fe0.2O3-δ材料的电化学性能进行了研究,并与自制的La0.2Sr0.8MnO3(LSM)氧电极材料进行了比较.结果表明:850℃下阳极极化阻抗(ASR)仅为0.07Ωcm2,远低于LSM;将其应用于SOEC氧电极进行高温电解制氢试验,产氢速率为相同条件下LSM的2.3倍,说明将Ba0.5Sr0.5Co0.8Fe0.2O3-δ用作SOEC阳极材料具有很好的应用前景.     

高温固体氧化物电解制氢技术

高温水蒸气电解制氢是解决大规模氢源问题的潜在途径之一。高温固体氧化物电解池（SOEC）可以利用各种可再生能源以及先进核能提供的热能和电能,在高温下将水蒸气高效电解为氢气和氧气。SOEC结合先进核能可以实现高达50%的热氢转化效率,已经成为近年来能源领域的一个研究热点。本文较详细介绍了SOEC的原理、分类、组成材料和特点,综述了SOEC制氢的发展现状、关键材料和核心技术,展望了SOEC在先进能源技术领域的应用前景。     

高温固体氧化物电解水制氢技术

高温水蒸气电解制氢是解决大规模氢源问题的潜在途径之一。高温固体氧化物电解池（SOEC）可以利用各种可再生能源以及先进核能提供的热能和电能,在高温下将水蒸气高效电解为氢气和氧气。SOEC结合先进核能可以实现高达50％的热氢转化效率,已经成为近年来能源领域的一个研究热点。本文较详细介绍了SOEC的原理、分类、组成材料和特点,综述了SOEC制氢的发展现状、关键材料和核心技术,展望了SOEC在先进能源技术领域的应用前景。     

中温固体氧化物燃料电池阴极材料LaBiMn2O6的制备与性能研究

采用固相法合成了中温固体氧化物燃料电池(IT-SOFCs)阴极材料LaBiMn₂O₆,并利用X射线衍射(XRD)和电化学阻抗谱(EIS)进行表征.结果表明该材料与电解质Ce_0.7Bi_0.3O_1.85(CBO)在1 000 ℃烧结12 h不发生反应.交流阻抗和直流极化测试结果发现,阴极极化电阻随测试温度的增加而逐渐减小,700 ℃空气中的极化电阻为0.71 Ω·cm²;氧分压测试结果显示,在600~700 ℃范围内,电极反应的速率控制步骤为电极上发生的电荷转移反应.电极过电位为85 mV时,700 ℃的阴极电流密度达到 216 mA·cm^-2 ,表明LaBiMn₂O₆是一种潜在的中温固体氧化物燃料电池(IT-SOFCs)阴极材料.     

氧分压对固体氧化物电解池性能的影响（英文）

基于固体氧化物电解池的高温电解水蒸气是一种可以在低碳排放条件下实现大规模氢气制备的技术。固体氧化物电解池的工作条件,尤其是所通入的气体组成和压力对其性能有很大的影响。本文基于计算流体力学软件建立了电解池理论模型来研究固体氧化物电解池的氧电极上通入不同氧分压的吹扫气对电解池反应特性的影响,文中所研究的氧分压范围为1.01×10~3–1.0×10~5 Pa。结果表明,可逆的开路电压随着氧分压的提高而增大,然而由活化极化、欧姆极化和浓差极化共同作用导致的极化电压随着氧分压增大而降低。在低电流密度时氧分压越小固体氧化物电解池性能越好,而在高电流密度时氧分压越大固体氧化物电解池性能越好。因此在低电流密度时采用低氧分压吹扫气有利于降低电解过程的耗电量,在高电流密度时采用氧气作为吹扫气有利于减少电解水的电能消耗并能够得到纯氧作为副产物以提高经济价值。     

高温固体氧化物电解制氢技术发展现状与展望

固体氧化物电解池是一种先进的能量转换装置,具有高效、简单、灵活、环境友好等特点,是目前国际能源领域的研究热点. 本文对高温固体氧化物电解制氢技术的基本原理、关键材料、系统组成、发展历程及国内外研究现状等进行了总结和分析,小结了该技术发展面临的主要挑战,简述了清华大学在高温固体氧化物电解领域近期的研究进展,并对其未来应用前景进行了展望.     

中温固体氧化物燃料电池阴极材料LaBiMn2O6的制备与性能

采用固相法合成了中温固体氧化物燃料电池(IT-SOFCs)阴极材料LaBiMn₂O₆,并利用X射线衍射(XRD)和电化学阻抗谱(EIS)进行表征。结果表明该材料与电解质Ce_0.7Bi_0.3O_1.85(CBO)在1000℃烧结12h不发生反应。交流阻抗和直流极化测试结果发现,阴极极化电阻随测试温度的增加而逐渐减小,700℃空气中的极化电阻为0.71Ω·cm²;氧分压测试结果显示,在600~700℃范围内,电极反应的速率控制步骤为电极上发生的电荷转移反应。电极过电位为85mV时,700℃的阴极电流密度达到216mA·cm^-2,表明LaBiMn₂O₆是一种潜在的中温固体氧化物燃料电池(IT-SOFCs)阴极材料。     

高温共电解H2O/CO2制备清洁燃料

高温共电解(high temperature co-electrolysis,HTCE)H2O和CO2技术是一种很有前景的清洁燃料制备和CO2减排新技术。该技术可利用可再生能源或核能提供的电能和高温热,通过高温固体氧化物电解池(solid oxide electrolysis cell,SOEC)将H2O和CO2共电解生产合成气(H2+CO),再将制备的合成气用于生产各种液态碳氢燃料。本文详细介绍了利用高温固体氧化物电解池共电解H2O和CO2制备合成燃料的基本原理、发展历程和目前世界各国的研究进展,对该技术的优势和特点进行了分析,并对该技术在关键材料、反应机理等方面存在的问题进行了总结和讨论,最后对其在新能源技术领域的应用前景作了展望。     

镍高度分散在铁基钙钛矿用于高温固体氧化物电解池阴极的CO2电催化还原研究(英文)

利用太阳能、风能等可再生清洁电能将CO₂催化转化为高附加值化学品或燃料,在CO₂转化和可再生电能存储方面表现出极具潜力的应用前景.高温固体氧化物电解池(SOEC)可将CO₂电催化还原为CO,具有能量效率高、成本低等优点.目前,钙钛矿氧化物已被广泛应用于SOEC电解CO₂的阴极材料,但存在电极催化活性低等问题,因而限制其规模化发展和应用.通常采用浸渍、原位溶出或掺杂等策略引入大量活性中心以提升钙钛矿氧化物电极性能.然而,这些策略仍然面临一些挑战,如浸渍法易引入大颗粒物种而堵塞气体传输通道,原位溶出法能耗较大且析出量较少,掺杂法调控活性幅度有限.因此,发展新型简便方法以合理构建具有高度分散活性位点的阴极材料,可有效拓展电化学三相反应界面,进而加快SOEC高温电解CO₂的电极动力学速率.本文采用机械研磨法将1.0%NiO高度分散于La_0.8Sr_0.2Fe0_3-δ-Ce_0.8Sm_0.2     

氧分压对固体氧化物电解池性能的影响

High-temperature (700–900 ℃) steam electrolysis based on solid oxide electrolysis cells (SOECs) is valuable as an efficient and clean path for large-scale hydrogen production with nearly zero carbon emissions, compared with the traditional paths of steam methane reforming or coal gasification. The operation parameters, in particular the feeding gas composition and pressure, significantly affect the performance of the electrolysis cell. In this study, a computational fluid dynamics model of an SOEC is built to predict the electrochemical performance of the cell with different sweep gases on the oxygen electrode. Sweep gases with different oxygen partial pressures between 1.01 × 10³ and 1.0 × 10⁵ Pa are fed to the oxygen electrode of the cell, and the influence of the oxygen partial pressure on the chemical equilibrium and kinetic reactions of the SOECs is analyzed. It is shown that the rate of increase of the reversible potential is inversely proportional to the oxygen partial pressure. Regarding the overpotentials caused by the ohmic, activation, and concentration polarization, the results vary with the reversible potential. The Ohmic overpotential is constant under different operating conditions. The activation and concentration overpotentials at the hydrogen electrode are also steady over the entire oxygen partial pressure range. The oxygen partial pressure has the largest effect on the activation and concentration overpotentials on the oxygen electrode side, both of which decrease sharply with increasing oxygen partial pressure. Owing to the combined effects of the reversible potential and polarization overpotentials, the total electrolysis voltage is nonlinear. At low current density, the electrolysis cell shows better performance at low oxygen partial pressure, whereas the performance improves with increasing oxygen partial pressure at high current density. Thus, at low current density, the best sweep gas should be an oxygen-deficient gas such as nitrogen, CO₂, or steam. Steam is the most promising because it is easy to separate the steam from the by-product oxygen in the tail gas, provided that the oxygen electrode is humidity-tolerant. However, at high current density, it is best to use pure oxygen as the sweep gas to reduce the electric energy consumption in the steam electrolysis process. The effects of the oxygen partial pressure on the power density and coefficient of performance of the SOEC are also discussed. At low current density, the electrical power demand is constant, and the efficiency decreases with growing oxygen partial pressure, whereas at high current density, the electrical power demand drops, and the efficiency increases.     

Advance in highly efficient hydrogen production by high temperature steam electrolysis

High Temperature Steam Electrolysis (HTSE) through a solid oxide electrolytic cell (SOEC) has been receiving increasing research and development attention worldwide because of its high conversion efficiency (about 45%-59%) and its potential usage for large-scale production of hydrogen. The mechanism, composition, structure, and developing challenges of SOEC are summarized. Current situation, key materials, and core technologies of SOEC (solid oxide electrolytic cell) in HTSE are re- viewed, and the prospect of HTSE future application in advanced energy fields is proposed. In addition, the recent research achievements and study progress of HTSE in Tsinghua University are also intro- duced and presented.     

Composite Cathode Based on Redox-Reversible Nb2TiO7 for Direct High-Temperature Steam Electrolysis

Ni/YSZ fuel electrodes can only operate under strongly reducing conditions for steam electrolysis in an oxide-ion-conducting solid oxide electrolyzer (SOE). In atmosphere with a low content of H₂ or without H₂, cathodes based on redox-reversible Nb₂TiO₇ provide a promising alternative. The reversible changes between oxidized Nb₂TiO₇ and reduced Nb_1.33Ti_0.67O₄ samples are systematically investigated after redox-cycling tests. The conductivities of Nb₂TiO₇ and reduced Nb_1.33Ti_0.67O₄ are studied as a function of temperature and oxygen partial pressure and correlated with the electrochemical properties of the composite electrodes in a symmetric cell and SOE at 830 oC. Steam electrolysis is then performed using an oxide-ion-conducting SOE based on a Nb_1.33Ti_0.67O₄ composite fuel electrode at 830 oC. The current-voltage and impedance spectroscopy tests demonstrate that the reduction and activation of the fuel electrode is the main process at low voltage; however, the steam electrolysis dominates the entire process at high voltages. The Faradic efficiencies of steam electrolysis reach 98.9% when 3%H₂O/Ar/4%H₂ is introduced to the fuel electrode and 89% for that with introduction of 3%H₂O/Ar.     

锰电解过程关键因素研究及技术经济性分析

从槽液Mn²⁺浓度、电解时间和过电位关键因素研究电解初期过程,在三电极体系采用计时电量法探讨和优化工艺参数. 研究表明,在不锈钢表面,锰的初期电解析氢显著. 随时间延长,锰逐渐覆盖于不锈钢表面,析氢更困难,其电流效率随之提升,在高过电位区出现极限电流,反应受扩散控制. 在含0.02 g·L^-1 SeO₂溶液体系中,在40 g·L^-1 Mn²⁺ + 120 g·L^-1 (NH₄)₂SO₄、过电位为0.151 V、槽液温度为40 ^oC、PH为6.6、时间为0.5 h的电解条件下,电流效率可达95.3%;在实用矿粉制液体系,效率也可达81.4%,较企业相同电解体系提高了15%.     

Characteristics of hydrogen nanobubbles in solutions obtained with water electrolysis

A solution supersaturated with hydrogen obtained by water electrolysis was studied using cyclic voltammetry. The cyclic voltammogram of the solution supersaturated with hydrogen gave a peak current at −0.1 V vs. AgAgCl. No peak current in a solution saturated with hydrogen was observed by bubbling hydrogen gas through the solution. The peak current was influenced by the temperature and ion type of the electrolyte. The peak current was found to be due to the presence of hydrogen nanobubbles. The peak current increased with increasing hydrogen nanobubble concentration and decreased to zero within 3 h after electrolysis.     

Power‐to‐Syngas: An Enabling Technology for the Transition of the Energy System?

Power‐to‐X concepts promise a reduction of greenhouse gas emissions simultaneously guaranteeing a safe energy supply even at high share of renewable power generation, thus becoming a cornerstone of a sustainable energy system. Power‐to‐syngas, that is, the electrochemical conversion of steam and carbon dioxide with the use of renewably generated electricity to syngas for the production of synfuels and high‐value chemicals, offers an efficient technology to couple different energy‐intense sectors, such as “traffic and transportation” and “chemical industry”. Syngas produced by co‐electrolysis can thus be regarded as a key‐enabling step for a transition of the energy system, which offers additionally features of CO₂‐valorization and closed carbon cycles. Here, we discuss advantages and current limitations of low‐ and high‐temperature co‐electrolysis. Advances in both fundamental understanding of the basic reaction schemes and stable high‐performance materials are essential to further promote co‐electrolysis.     

煤沥青的电化学加氢：Ⅱ.精制沥青的电化学加氢

在隔离式是电解中，用泡沫铅作用阴极，铂作阳极，饱和甘汞电极做参考电极，对太原钢铁公司焦化厂煤沥青经溶剂萃取后所得的精制沥青进行了电化学加氢的研究，考察了电解体系工艺条件对加氢效果的影响。     

固体氧化物燃料电池阳极材料研究及其在高温水电解制氢方面的应用

本文综述了固体氧化物燃料电池阳极材料的研究现状和进展。详细地介绍了国内外固体氧化物燃料电池阳极材料的制备、改性、微观结构与性能关系以及阳极反应动力学机理,并对各种材料适用的条件和优缺点进行了比较。对阳极材料在高温电解制氢领域阴极上的应用前景进行了展望。     

电池电极反应的新应用：分步法电解制氢气

可再生能源与电解水制氢技术的结合是实现可持续制氢的最佳途径. 然而,传统电解水技术中解决氢-氧同时、同步、同地产生的问题必须依赖于膜分离技术,大幅限制了氢-氧分离和氢气异地运输的灵活性,并阻碍了可再生能源(如风能、太阳能)与电解水技术的直接结合. 针对上述问题,作者课题组在近期提出了基于电池电极反应的分步法电解水制氢技术,即通过电池电极的可逆电化学反应将现有电解水过程拆分为制氢和制氧分立步骤,实现在无膜条件下氢气和氧气的分时、分地交替制备,提升了电解水制氢的灵活性,促进了可再生能源向氢能的直接转化. 本文将介绍这一新技术的研究进展,并分析这一技术的优点和面临的挑战.     

基于可再生能源的水电解制氢技术（英文）

在全球变暖,污染日益严重的今天,发展可再生清洁能源成为了当务之急.然而可再生能源(风能、太阳能)本身具有间断特性,这就需要寻找一种合适的能量媒介储存能量来保证其能源的稳定输出.当前,我国各地不断出现弃风、弃光和弃水电事件,据国家能源局的公开数据,仅2016年,全国弃风电量497×10~8 kW·h,弃光率仅西部地区就已达20%,弃风弃光日臻凸显[1].从地域方面来看,我国光伏发电呈现东中西部共同发展格局,其中,西部地区主要发展集中式光伏发电,新疆、甘肃、青海、宁夏的累计装机容量均超过5×10~6 k W·h,而中东部地区除集中式光伏发电外,还重点建设分布式光伏发电,江苏、浙江、山东、安徽的分布式光伏装机规模已超过100万千瓦.我国光伏发电集中开发的西北地区也存在严重的弃光问题.根据中国光伏行业协会发布的报告,我国的弃光现象主要集中于西北的新疆、甘肃、青海、宁夏和陕西五省区.据统计,2016年,五省区光伏发电量287.17×10~8 k W·h,弃光电量70.42×10~8 k W·h,弃光率为19.81%,各省区光伏发电并网运行数据如表格所示.可以看出,新疆、甘肃光伏发电运行较为困难,弃光电量绝对值高,弃光率分别达到32.23%和30.45%[2].在新能源体系中,氢能是一种理想的二次能源,与其它能源相比,氢热值高,其能量密度(140 MJ/kg)是固体燃料(50MJ/kg)的两倍多.且燃烧产物为水,是最环保的能源,既能以气、液相的形式存储在高压罐中,也能以固相的形式储存在储氢材料中,如金属氢化物、配位氢化物、多孔材料等.对可再生和可持续能源系统,氢气是一种极好的能量存储介质.氢气作为能源载体的优势在于:(1)氢和电能之间通过电解水技术可实现高效相互转换;(2)压缩的氢气有很高的能量密度;(3)氢气具有成比例放大到电网规模应用的潜力.制氢的方式有很多,包括:化石燃料重整、分解、光解或水解等.全球每年总共需要约40亿吨氢气,95%以上的氢气是通过化石燃料重整来获得,生产过程必然排出CO_2,而电解水技术利用可再生能源获得的电能进行规模产氢,可实现CO_2的零排放,可将具有强烈波动特性的风能、太阳能转换为氢能,更利于储存与运输.所存储的氢气可用于燃料电池发电,或单独用作燃料气体,也可作为化工原料.通过水电解方式获得的氢气纯度较高,可达99.9%以上.