熔融碳酸盐燃料电池阴极溶解与防护北大核心CSCD

熔融碳酸盐燃料电池(MCFC)是一种高效、可持续发电技术,其能源转换效率高、排放净化度高,是一种极具前途的发电技术。但是,由于其高工作温度和熔融碳酸盐电解质的特殊性质,MCFC的发展一直受到阻碍。其中,阴极溶解是一个严重的问题,会导致Ni短路等一系列问题,影响燃料电池的性能和寿命。本文综述了降低熔融碳酸盐燃料电池阴极溶解的策略,简述了近年来从替代材料、涂层改性和添加剂三个方面对阴极溶解的改善研究,探讨了替代NiO材料的方案不完全可行的问题,并提出了使用涂层技术来增强NiO阴极化学性能和降低阴极溶解度的可能性。涂层技术的优缺点也被详细列举,包括溶液浸渍电镀、溶胶-凝胶工艺和原子层沉积等一系列研究进展和性能。此外,本文还探讨了增加电解液碱度和向NiO中添加碱性氧化物来减少阴极溶解的方法,但也指出添加过多氧化物会降低电池性能的风险。综合分析表明,通过开发新型添加剂和涂层技术弥补合金作为阴极材料的性能缺陷,尝试制备新型复合材料等途径,有望获得高性能、低成本的阴极材料,从而实现MCFC的大规模商业化应用。     

MCFC-燃气轮机联合循环系统模拟与优化

熔融碳酸盐燃料电池（MCFC）工作温度较高,其高温排气可由燃气轮机利用,组成联合发电系统。文中分别建立了MCFC和底层循环的计算模型,利用该模型详细分析了影响联合发电系统性能的重要参数。结果表明：将MCFC工作温度取为650℃可以得到最佳性能和最高的电堆寿命;联合发电系统中应取较低的燃料气利用率;在一定的透平初温下,燃气轮机存在一个对应于功率最大的最佳压缩比。根据上述结果计算出了各参数的最优值,最后对优化后系统进行仿真得出结果：MCFE与燃气轮机组成联合发电系统,发电效率达到57．0％（LHV）,使用燃气轮机可提升整体发电效率约10％。     

熔融碳酸盐燃料电池热启动过程的人工神经网络建模

熔融碳酸盐燃料电池(MCFC)是燃料电池研究领域的一个难点,其严格的热启动过程对电池性能和寿命的影响至关重要.针对这一问题,建立了基于人工神经网络的熔融碳酸盐燃料电池热启动过程模型,并详细给出了采用改进BP算法的熔融碳酸盐燃料电池热启动过程的模型结构、算法、训练和仿真.MATLAB仿真结果证明其快速准确,为熔融碳酸盐燃料电池热启动过程的控制提供了实际工程应用模型.     

Fundamental scientific aspects of lithium ion batteries (Ⅸ)----Nonaqueous electrolyte materials

电解质是锂离子电池的重要组成部分,它起着在正负极之间传输Li⁺的作用.因此,电解质的研究与开发对锂离子电池来说至关重要,然而综合性能优异,满足不同应用的电解液并不容易开发.本文简介了非水液体电解质的发展历史和基本性质,然后分别从锂盐,溶剂和添加剂方面进行论述,最后介绍了离子液体,凝胶聚合物电解质和高电压电解质,认为未来锂离子电池电解质要解决的问题有:电解液和电池的安全性,提高电解质的工作电压,拓宽其工作温度范围,延长电池寿命和降低成本.     

全固态锂离子电池关键材料研究进展

全固态锂离子电池采用固态电解质替代传统有机液态电解液,有望从根本上解决电池安全性问题,是电动汽车和规模化储能理想的化学电源。为了实现大容量化和长寿命,从而推进全固态锂离子电池的实用化,电池关键材料的开发和性能的优化刻不容缓,主要包括制备高室温电导率和电化学稳定性的固态电解质以及适用于全固态锂离子电池的高能量电极材料、改善电极/固态电解质界面相容性。本文以全固态锂离子电池关键材料为出发点,综述了不同类型的固态电解质和正负极材料性能特征以及电极/电解质界面性能的调控和优化方法等,阐述了未来全固态锂离子电池关键材料的发展方向以及界面问题的解决思路,为探索全固态锂离子电池产业化前景奠定基础。     

Recent advances of electrolytes for sodium-ion batteries

作为一种新型的储能电池体系,钠离子电池具有资源丰富、成本低、比容量较高等优点,近年来引起了全世界范围内的广泛关注。电解质是制备高性能,长循环寿命,安全性良好的钠离子电池的关键材料之一。本文简要介绍有机电解质、水系电解质、离子液体电解质、固体聚合物电解质、无机固态复合电解质和凝胶态聚合物电解质等体系在钠离子电池中的研究进展,讨论这些电解质体系的电导率、电化学窗口、热稳定性等特点。目前应用在钠离子电池中较为成熟的是有机电解质,展现了良好的综合性能,但安全性仍有待改善。而安全性能较好的离子液体电解质、固体电解质及凝胶态电解质还有许多基础科学需要探索,并且需要考虑成本、电导率、机械强度等诸多因素。基于上述评述,展望了钠离子电池电解质的未来发展。     

碳酸盐燃烧电池发电技术—一种清洁、高效的发电技术

碳酸盐燃烧电池（以下简称MCFC），采用天然气或是合成煤气作燃料，提供了一个清洁，高效的发电方式，并被认为是将来最具有前途的发电技术，本着重从原理方面对MCFC技术进行分析，引入了几个基本概念，对最基本的MCFC工艺进行描述，最后，介绍了了提高燃料电池电厂效率的两种工艺。     

绿色“火力”发电厂——面向21世纪的燃烧电池

熔融碳酸盐燃料电池（MCFC）发电是新世纪的高效、洁净的发电技术,特别是它可取代传统的燃煤、燃气火力发电,彻底解决火力发电污染大、效率低的弊端。本文首先分析了开发MCFC发电厂的必要性及资源条件;然后首次从电极、单电池、电堆、系统四个层次阐述了MCFC燃料电池的发电原理,并分析了四个层次中发生的主要热、电过程;给出了天然气MCFC发电厂、煤气化MCFC-燃气轮机-汽轮机联合发电厂的构成和主要过程。最后阐明了我国大力研究和开发MCFC发电厂的现实意义。     

熔融碳酸盐燃料电池（MCFC）系统建模与控制的研究现状与发展

详细介绍了MCFC的电极,单电池、电堆,系统四个层次的建模以及MCFC控制的研究现状,指出了现有模型的不足;讨论了电堆和系统两级建模的发展方向,分析了MCFC系统的非线性,大时滞、分布参数、多输入多输出,有约束和随机干扰等特征,提出了两种适宜的控制方法。     

基于加权残值法的高温燃料电池温度分布特性的数值分析

加权残值法是一种可以直接从偏微分方程中求得近似解的数学方法。通过对熔融碳酸盐燃料电池(MCFC)内部传热传质过程的热力学性能分析,在质量守恒和能量守恒的基础上建立了MCFC温度动态分布的数学模型,并采用加权残值法对其进行求解分析。确定了满足模型边界条件的试函数,以三次正交多项式为基函数,利用加权残值法中的迦辽金法,结合Matlab工具得到MCFC温度的动态分布特性曲线。分析结果表明,燃料电池内部各点温度在空间分布上有很大差异;当供给燃料电池的燃料流量和氧化剂流量变化时,所引起的温度动态特性是复杂的。图3参5。     

MCFC performance diagnosis by using the current-pulse method

Several problems prevent molten carbonate fuel cells (MCFC) operation for an extended period. However, if the degradation factors can be identified and resolved in a timely manner, MCFC could become a valuable technology. Therefore, a performance diagnosis should be developed which enables the simple and instantaneous determination of MCFC degradation factors. A suitable six parameter equation obtained by a current-pulse method, obtainable from MCFC's transient response in 100 ms, is expressible in an equivalent circuit composed of three sub-circuits. The relationship between these parameters and each degradation factor is evaluated by a single MCFC cell, the electrode area of which is 16 cm². Degradation factors include cross-leakage, electrolytic loss, cell temperature distribution and gas composition/flow rate. As a result, each of six parameters in the MCFC transient response corresponds to an ohmic potential drop, anode/cathode gas diffusion resistance, reactive resistance, three-phase interfacial resistance and electrolyte properties, respectively. The proposed performance diagnosis specifies the degradation factors by combining the six parameters. Performance diagnosis was applied to a single MCFC cell of an electrode area of 81 cm in extended operations, and the degradation factor diagnosed. As a result, the diagnosis was able to specify the cell degradation factors from the degradation factor ratio, corresponding to cell voltage, cell resistance and the N₂ concentration of MCFC single cell performance. Therefore, the proposed performance diagnosis is able to easily specify the driven MCFC degradation factors in a timely manner.     

MCFC-并联TTEG混合系统的性能优化

为有效回收熔融碳酸盐燃料电池产生的余热,提出一种由熔融碳酸盐燃料电池(MCFC)、两级并联温差发电器(TTEG)和回热器组合而成的混合系统模型.考虑MCFC电化学反应中的过电势损失和混合系统中的不可逆损失,通过数值分析得出混合系统的输出功率和效率的数学表达式,获得混合系统的一般性能特征,讨论MCFC电流密度与温差发电器...     

Performance analysis of a pressurized molten carbonate fuel cell/micro-gas turbine hybrid system

This paper presents the work on the design and part-load operations of a hybrid power system composed of a pressurized molten carbonate fuel cell (MCFC) and a micro-gas turbine (MGT). The gas turbine is an existing one and the MCFC is assumed to be newly designed for the hybrid system. Firstly, the MCFC power and total system power are determined based on the existing micro-gas turbine according to the appropriate MCFC operating temperature. The characteristics of hybrid system on design point are shown. And then different control methods are applied to the hybrid system for the part-load operation. The effect of different control methods is analyzed and compared in order to find the optimal control strategy for the system. The results show that the performance of hybrid system during part-load operation varies significantly with different control methods. The system has the best efficiency when using variable rotational speed control for the part-load operation. At this time both the turbine inlet temperature and cell operating temperature are close to the design value, but the compressor would cross the surge line when the shaft speed is less than 70% of the design shaft speed. For the gas turbine it is difficult to obtain the original power due to the higher pressure loss between compressor and turbine.     

Modeling the performance of MCFC for various fuel and oxidant compositions

100 cm² molten carbonate fuel cells (MCFC) was used for testing the fuel and oxidant composition influence on MCFC performance as a temperature function.     

Control‐oriented nonlinear modelling of molten carbonate fuel cells

Performance and availability of molten carbonate fuel cells (MCFC) stack are greatly dependent on its operating temperature. Control of the operating temperature within a specified range and reduction of its temperature fluctuation are highly desirable. The models of MCFC stack existing are too complicated to be suitable for design of a controller because of its lack of clear input–output relations. In this paper, according to the demands of control design, a quantitative relations model of control‐oriented MCFC between the temperatures of the stack and flowrates of the input gases is developed, based on conservation laws. It is an affine nonlinear model with multi‐input and multi‐output, the flowrates of fuel and oxidant gases as the manipulated vector and the temperatures of MCFC electrode–electrolyte plates, separator plates as the controlled vector. The modelling and simulation procedures are given in detail. The simulation tests reveal that the model developed is accurate and it is suitable to be used as a model in designing a controller of MCFC stack. Copyright © 2004 John Wiley & Sons, Ltd.     

A feasibility assessment of a retrofit Molten Carbonate Fuel Cell coal-fired plant for flue gas CO2 segregation

This work considers the use of a Molten Carbonate Fuel Cell (MCFC) system as a power generation and CO₂ concentrator unit downstream of the coal burner of an existing production plant. In this way, the capability of MCFCs for CO₂ segregation, which today is studied primarily in reference to large-scale plants, is applied to an intermediate-size plant highlighting the potential for MCFC use as a low energy method of carbon capture. A technical feasibility analysis was performed using an MCFC system-integrated model capable of determining steady-state performance across varying feed composition. The MCFC user model was implemented in Aspen Custom Modeler and integrated into the reference plant in Aspen Plus. The model considers electrochemical, thermal, and mass balance effects to simulate cell electrical and CO₂ segregation performance. Results obtained suggest a specific energy requirement of 1.41 MJ kg CO₂^?1 significantly lower than seen in conventional Monoethanolamine (MEA) capture processes.     

A basic model for analysis of molten carbonate fuel cell behavior

A simple mathematical model, based on the basic chemical reactions and mass transfer, was developed to predict some important characteristics of molten carbonate fuel cells (MCFC) with LiNaCO₃ and LiKCO₃ electrolytes for steady state operating conditions. The parallel and cross gas flow patterns were analyzed. Model simulates polarization characteristics, the effect of temperature, pressure and electrolyte type on the cell performance, various losses in the cell and gas flow rate changes through cell. The effect of fuel utilization on the cell potential and efficiency was also analyzed. Model predicts a better performance for the MCFC with LiNaCO₃ electrolyte and the cross flow pattern, in general. Results show a strong influence of the operating temperature on the cell potential at temperatures below 625 °C, where cell potential increases rapidly with increasing temperature. Above this temperature, however, the cell potential has almost a steady asymptotic profile. The model predicts cell efficiency steadily improving with increase in fuel utilization. The cell potential decreases almost linearly with increase in the fuel utilization percentage for both electrolytes. Models results show a stronger dependency of the cell potential on the operating pressure than that described by the Nerst equation which is in line with fact that the real variations in the cell potential can be higher due to decreased various losses.     

Recycling electronic scrap to make molten carbonate fuel cell cathodes

The paper aims to examine the possibility of improving the manufacturing process for MCFC cathodes. using noble, semi-precious, and rare earth metals sourced from waste electric and electronic equipment (WEEE). As MCFC components are not particularly sensitive to ceramic and metal impurities. The addition of noble metals recovered from WEEE as catalysts are economically justifiable. The reported experimental research revealed the positive impact of MCFC cathode fabricated with 20% recycled electronic scrap. Especially the cell with powder marked as 4/1 enjoyed much better performance operating at 550 °C than the reference cell. During the operation at a temperature of 650 °C, the cell with powder marked as 4/1 has almost the same performance as the reference cell, i.e., 1.01 V OCV and power density of 0.13 A/cm². The cell with cathode with 4/2 powder has the worst performance – current density of 0.09 A/cm² and OCV of 0.97 V.     

A methodology for improving the performance of molten carbonate fuel cell/gas turbine hybrid systems

In the present article a molten carbonate fuel cell (MCFC) system has been developed, modeled and implemented in Matlab language. It enables definition of the optimal operating conditions of the fuel cell, in terms of electrical and thermal performance, when it is a part of a hybrid plant composed of an MCFC system, a gas turbine and a possible heat recovery system. The thermal energy, which is recoverable from the adequately treated anodic exhaust gases, is utilized in a gas turbine plant to reduce its fuel consumption. Therefore, in the present article a methodology is illustrated to calculate the optimal values of some parameters characterizing the MCFC/gas turbine integrated system in terms of the electrical, first law and equivalent efficiencies. A choice is made among the sets of values of parameters investigated to improve the performance of the same integrated system according to its use (for the production of electric energy only or for the contemporary production of electric and thermal energy). Copyright © 2010 John Wiley & Sons, Ltd.     

MCFC cathode dissolution: an alternative approach to face the problem

A solution to face the NiO dissolution problem in a molten carbonate fuel cell (MCFC) is hereafter proposed. In particular the performances of a cell in which a matrix layer has been replaced by a ferrite layer are discussed. Process gas analyses, internal resistance, open circuit voltage and V–I plots at constant gas flow and composition are the data collected to assess this technical solution in cell operating conditions.

In addition indications on pre and post-tests analyses are presented in order to underline the most important parameters to verify raw material suitability and the ferrite effectiveness on cathode dissolution.