Catalyst Engineering for Electrochemical Energy Conversion from Water to Water:Water Electrolysis and the Hydrogen Fuel Cell

In the context of the current serious problems related to energy demand and climate change,substantial progress has been made in developing a sustainable energy system.Electrochemical hydrogen-water conversion is an ideal energy system that can produce fuels via sustainable,fossil-free pathways.However,the energy conversion efficiency of two functioning technologies in this energy system—namely,water electrolysis and the fuel cell—still has great scope for improvement.This review analyzes the energy dissipation of water electrolysis and the fuel cell in the hydrogen-water energy system and discusses the key barriers in the hydrogen-and oxygen-involving reactions that occur on the catalyst surface.By means of the scaling relations between reactive intermediates and their apparent catalytic performance,this article summarizes the frameworks of the catalytic activity trends,providing insights into the design of highly active electrocatalysts for the involved reactions.A series of structural engineering methodologies(including nano architecture,facet engineering,polymorph engineering,amorphization,defect engineering,element doping,interface engineering,and alloying)and their applications based on catalytic performance are then introduced,w让h an emphasis on the rational guidance from previous theoretical and experimental studies.The key scientific problems in the electrochemical hydrogen-water conversion system are outlined,and future directions are proposed for developing advanced catalysts for technologies with high energy-conversion efficiency.

CO_(2) conversion to solar fuels and chemicals:Opening the new paths

This future article discusses the new prospects and directions of CO_(2)conversion via the photo-electrocatalytic(PEC)route.The second(2nd)generation solar fuels and chemicals(SFs)are generated directly in PEC systems via electrons/protons reactions without forming molecular H_(2)as an intermediate,overcoming the thermodynamics limitations and practical issues encountered for electro-fuels produced by multistep thermocatalytic processes(i.e.CO_(2)conversion with H_(2)coming from water electrolysis).A distributed and decentralized production of SFs requires very compact,highly integrated,and intensified technologies.Among the existing reactors of advanced design(based on artificial leaves or photosynthesis),the integrated photovoltaic plus electrocatalytic(PV-EC)device is the only system(demonstrated at large scale)to produce SFs with high solar-to-fuel(STF)efficiency.However,while the literature indicates STF efficiency as the main(and only)measure of process performance,we remark here the need to refer to productivity(in terms of current density)and make tests with reliable flow PEC systems(with electrodes of at least 5–10 cm^(2))to accelerate the scaling-up process.Using approaches that minimize downstream separation costs is also mandatory.Many limitations exist in PEC systems,but most can be overcome by proper electrode and cell engineering,thus going beyond the properties of the electrocatalysts.As examples of current developments,we present the progress of(i)artificial leaf/tree devices for green H_(2)distributed production and(ii)a PEC device producing the same chemicals at both cathode and anode parts without downstream operations for green solvent distributed production.Based on these developments,future directions,such as producing fertilizers and food components from the air,are outlined.The aim is to provide new ideas and research directions from a personal perspective.

Research on the technical scheme of multi-stack common rail fuel cell engine based on the demand of commercial vehicle

At present,most fuel cell engines are single-stack systems,and high-power single-stack systems have bottlenecks in meeting the power requirements of heavy-duty trucks,mainly because the increase in the single active area and the excessive number of cells will lead to poor distribution uniformity of water,gas and heat in the stack,which will cause local attenuation and reduce the performance of the stack.This paper introduces the design concept of internal combustion engine,takes three-stack fuel cell engine as an example,designs multi-stack fuel cell system scheme and serialized high-voltage scheme.Through Intelligent control technology of independent hydrogen injection based on multi-stack coupling,the hydrogen injection inflow of each stack is controlled online according to the real-time anode pressure to achieve accurate fuel injection of a single stack and ensure the consistency between multiple stacks.proves the performance advantage of multi-stack fuel cell engine through theoretical design,intelligent control and test verification,and focuses on analyzing the key technical problems that may exist in multi-stack consistency.The research results provide a reference for the design of multi-stack fuel cell engines,and have important reference value for the powertrain design of long-distance heavy-duty and high-power fuel cell trucks.

Cruise/Simulink Combined Simulation for Fuel Cell Hybrid Vehicles

In order to accelerate the design of fuel cell(FC)/battery hybrid vehicles and optimize the related performance,a new modeling and simulation method for the fuel cell(FC)/battery hybrid vehicle was introduced in this paper.The co-simulation platform was set up by combining MATLAB/Simulink with AVL/Cruise,where the FC engine was realized in MATLAB/Simulink and the other most vehicle components were modeled in AVL/Cruise.The performance of a certain FC hybrid vehicle with the embedded FC engine was evaluated by using the platform.Simulation results show that this method of simulation can be applied for the design of power management strategy,power unit configuration,and performance evaluation of FC hybrid vehicles.

A Case Study of a Solid Oxide Fuel Cell Plant on Board a Cruise Ship

The work is a case study of a cruise ship supplied by liquefied natural gas(LNG)and equipped with a solid oxide fuel cell(SOFC).It is supposed that a 20 MW SOFC plant is installed on-board to supply hotel loads and assisting three dual-fuel(DF)diesel/LNG generator sets.LNG consumption and emissions are estimated both for the SOFC plant and DF generator sets.It results that the use of LNG-SOFC plant in comparison to DF generator sets allows to limit significantly the SO_(x),CO,NO_(x),PM emissions and to reduce the emission of CO_(2)by about 11%.A prediction of the weight and volume of the SOFC plant is conducted and a preliminary modification of the general arrangement of the cruise ship is suggested,according to the latest international rules.It results that the SOFC plant is heavier and occupies more volume on board than a DF gen-set;nevertheless,these features do not affect the floating and the stability of the cruise ship.

Process engineering in electrochemical energy devices innovation

This review focuses on the application of process engineering in electrochemical energy conversion and storage devices innovation. For polymer electrolyte based devices, it highlights that a strategic simple switch from proton exchange membranes(PEMs) to hydroxide exchange membranes(HEMs) may lead to a new-generation of affordable electrochemical energy devices including fuel cells, electrolyzers, and solar hydrogen generators. For lithium-ion batteries, a series of advancements in design and chemistry are required for electric vehicle and energy storage applications. Manufacturing process development and optimization of the LiF eP O_4/C cathode materials and several emerging novel anode materials are also discussed using the authors' work as examples.Design and manufacturing process of lithium-ion battery electrodes are introduced in detail, and modeling and optimization of large-scale lithium-ion batteries are also presented. Electrochemical energy materials and device innovations can be further prompted by better understanding of the fundamental transport phenomena involved in unit operations.

The Energy Optimization Mathematic Algorithm on Multi-energy Resource Powertrain of Fuel Cell Vehicle

In order to solve the core issue of the energy regulation （ER） on multi-energy resource powertrain of fuel cell vehicle, the work functions of each component were defined; the mathematical algorithm model of energy regulation was established and the relevant solution was found. This algorithm was evaluated successfully on the hardware in loop （FILL） platform under three typical urban running cycles. The results showed ER control target had been realized and the mathematical algorithm was effective and reasonable. Based on the HIL simulation, some conclusions and ER strategies were made. According to the different power component parameters and real time control request, this algorithm should be modified and calibrated for application in the actual control system.

Application of Solid Oxide Fuel Cell-Auxiliary Power Unit on Different Trucks in Northeast China

A diesel engine of conventional trucks has a low efficiency under the idling condition,leading to a high cost for heating or cooling in the cab during night. The solution to this problem will have great significance on energy conservation and emission reduction. A new auxiliary power unit of solid oxide fuel cell( SOFCAPU) with high efficiency solves this problem perfectly. Heat pump air conditioner is considered as a promising device for the application of SOFC-APU with a high cooling and heating efficiency. To make a quantitative analysis for the application of SOFC-APU,a model is built in Matlab / Simulink. The diesel engine model and SOFC-APU model are fitted based on some experimental data of SOFC-APU and diesel engine during the idling operation. An analysis of the application of SOFC-APU on different trucks in Northeast China is comprehensively made,including efficiency and emission.

Design and Control of a DC Boost Converter for Fuel-Cell-Powered Marine Vehicles

Economic factors along with legislation and policies to counter harmful pollution apply specifically to maritime drive research for improved power generation and energy storage.Proton exchange membrane fuel cells are considered among the most promising options for marine applications.Switching converters are the most common interfaces between fuel cells and all types of load in order to provide a stable regulated voltage.In this paper,a method using artificial neural networks(ANNs)is developed to control the dynamics and response of a fuel cell connected with a DC boost converter.Its capability to adapt to different loading conditions is established.Furthermore,a cycle-mean,black-box model for the switching device is also proposed.The model is centred about an ANN,too,and can achieve considerably faster simulation times making it much more suitable for power management applications.

Fuel Cells as Energy Systems： Efficiency, Power Limits and Thermodynamic Behavior

Steady-state model of a high-temperature solid oxide fuel cell （SOFC） is considered, which refers to constant chemical potentials of incoming hydrogen fuel and oxidant. Lowering of the cell voltage below its reversible value is attributed to polarizations and imperfect conversions of reactions. An imperfect power formula summarizes the effect of transport laws, irreversible polarizations and efficiency of power yield. Reversible electrochemical theory is extended to the case with dissipative chemical reactions; this case includes systems with incomplete conversions, characterized by ＂reduced affinities＂ and an idle run voltage. Efficiency drop is linked with thermodynamic and electrochemical irreversibilities expressed in terms of polarizations （activation, concentration and ohmic）. Effect of incomplete conversions is modeled by assuming that substrates can be remained after the reaction and that side reactions may occur. Optimum and feasibility conditions are discussed for basic input parameters of the cell. Calculations of maximum power show that the data differ for power generated and consumed and depend on current intensity, number of mass transfer units, polarizations, electrode surface area, average chemical rate, etc.. These data provide bounds for SOFC energy generators, which are more exact and informative than reversible bounds for electrochemical transformation.

氢能技术及其在车用领域应用现状综述

化石燃料的快速消耗迫切地需要寻找绿色清洁的替代能源,氢能是一种来源丰富、绿色低碳、应用广泛的二次能源,具有高能量、无污染的特性,是当下重要的工业原料。本文较为全面地分析了氢能的制取与储存,并且围绕氢能在车用领域的应用,因为在碳峰值和碳中和的背景下,内燃机行业的发展正面临着最好的转型机遇。加快氢发动机关键技术的研发和应用已成为世界各国政府和各大汽车企业的重要战略。本文对比了氢燃料电池与氢燃料内燃机的特点,对未来氢能源利用的产业化前景进行了分析。

兆瓦级PEMFC系统的设计和应用

质子交换膜燃料电池(PEMFC)可实现电力和热力的联合供应,是支持零碳能源战略的重要技术路径。对兆瓦级PEMFC系统进行介绍与分析,对工程化应用中的实践提供逆变器、变压器、板式换热器和能量管理系统等部件的选型依据与建议,并指出在系统运行中自耗电占比最高的部件为空压机和散热风扇,分别占自耗电总功率的82.0%和10.7%。兆瓦级PEMFC系统在氯碱工厂中的商业化应用,可将原本排空的氢气发电,提高厂区能量利用效率,创造经济效益。

浅析氢燃料电池发动机及其辅助系统状态监测与故障诊断

氢燃料电池发动机作为氢能车辆核心动力单元,其电堆运行状态健康监测和故障诊断直接影响车辆使用和电堆的寿命。当前采用的监测手段主要是对电堆电流和电堆单片电压的监控,通过判断电堆各个单体的电压一致性,以及是否有出现个别单体电压低的问题来判断电堆的健康状态。存在的问题是没有对先期机械故障即早期零部件失效进行监控,电堆能否正常工作也受制于提供空气和冷却的主要零件空压机和水泵的影响,当前仅通过电压巡检器对电堆单体电压的监测被动的报警,当报警时已经出现零件机械结构问题需要车辆进站维修更换零部件,影响车辆的正常出勤。所以有必要通过振动信号进行空压机、水泵等零部件故障的先期诊断评估,并在车辆保养或者闲时进行维修,可避免影响车辆正常营运,减少客户抱怨。

氢能源飞机的现状与未来

航空运输业碳排放较高,因此计划用氢能源代替传统航空燃油以降低碳排放,以氢燃料电池和氢燃料航空发动机作为飞机的动力源。围绕氢能源本身,对氢燃料电池和氢燃料航空燃气涡轮发动机展开论述,总结氢能源发展的主要技术难题,为氢能源飞机发展提供参考。

基于甲醇燃料的航空燃料电池内燃机混合动力系统性能分析

为了实现航空碳减排的时代需求,亟需在航空燃料体系和航空动力系统方向实现技术革新。本文提出了基于甲醇燃料的航空燃料电池内燃机混合动力系统方案,甲醇通过机载在线催化重整制氢为燃料电池供氢,燃料电池和内燃机发出的电能带动电动螺旋桨进行工作。进行了模块化建模方法和混合动力系统性能仿真分析研究,结果表明:混合动力系统的发电效率达到了55%,相比甲醇内燃机有了15%绝对值的效率提升,有助于降低燃料消耗。进行了混合动力系统性能参数影响规律分析,结果表明:混合动力系统的效率随着压比的增大而提高,随着燃料利用率的提高而呈现先升高后降低的效果。进行了混合动力系统的?分析,结果显示:混合动力系统中?效率最高的部件是燃料电池,?损最大的部件是重整器。质量分析结果表明:混合动力系统的功率密度达到0.488 kW/kg。

FCE空气过滤吸附材料压降试验与仿真研究

对于燃料电池发动机(FCE)用空气过滤器,压降大小是其主要性能参数之一。活性炭对有害气体(SO2,NOX等)有良好的吸附性能,被用于FCE空气过滤器的吸附层材料。运用实验的方法测量了空气经过活性炭颗粒堆积物的压降与空气流速,以及压降与堆积高度的关系。利用CFD软件Fluent对空气经过活性炭颗粒堆积物的压降进行了仿真研究。研究结果表明,利用压降和速度的试验数据来计算粘性阻力系数1/α和惯性阻力系数C2由此得到的仿真结果和实验结果符合良好,仿真具有可靠性。

军用舰船动力装置技术应用现状及未来趋势展望

以动力装置对军用舰船的影响作为切入点,概要介绍舰船动力装置的定义及相关技术要求,并对柴油机、汽轮机、燃气轮机等几类常见动力装置的技术特点及应用现状进行重点研究,随后对相关动力装置的当前主要技术问题进行详尽阐述。最后,对上述舰船动力装置的未来发展趋势及相关技术研发策略开展重点研究。就目前而言。柴油机是中、小型舰船(涵盖各类水面舰船与潜艇)和军辅船的重点发展方向;燃料电池与斯特林发动机是常规潜艇不依赖空气的推进(AIP)系统的重点发展方向;汽轮机和燃气轮机是大、中型水面舰船动力装置的重点发展方向;核动力装置则是航空母舰与核潜艇的重点发展方向。考虑到国际局势的风云变幻,针对动力装置的设计、研发、制造与优化能进一步提升舰船的整体性能,为我国的海防事业作出不可磨灭的贡献。

低温燃料电池在汽车工程中的供储能特性分析

低温燃料电池作为一种先进的能源技术,其在汽车工程中的应用日益受到关注。首先,低温燃料电池技术可以直接将燃料(如氢气)的化学能转化为电能,无须经过燃烧过程,因此其能量转换效率远高于传统的内燃机。这种高效性使得低温燃料电池汽车能够在保证动力性能的同时,降低能源消耗,提高行驶里程。其次,低温燃料电池在反应过程中主要产生水和热,不产生有害的尾气和颗粒物,从而实现了零排放。此外,低温燃料电池可以使用可再生能源(如太阳能、风能等)产生的氢气作为燃料,从而实现能源的循环利用。综上,针对低温燃料电池在汽车工程中的供储能特性展开分析综述。

Nano-engineered catalysts for high-performance oxygen reduction reaction

The efficient energy conversion of fuel cells is greatly constrained by the slow oxygen reduction reac tion(ORR)kinetics,which necessitates the use of highly active metal catalysts such as platinum(Pt).The critical challenge limiting large-scale usage of Pt is the capital cost that can be addressed through a pro totypical approach by embedding metal nanoparticles(NPs),e.g.,Pt NPs,in the conductive framework However,previously reported embedding approaches are sophisticated and suffer from limited yields leading to higher chemical process costs and remaining distant from commercial viability.Here,we re port a facile,cost-effective and time-efficient structural tuning approach to synthesizing ultrafine Pt NP impregnated within a conductive and highly porous carbon framework via a microwave-assisted polyo reduction method.Pt NPs with a uniform size of~2.27 nm can be successfully integrated within the pore of the carbon framework,enabling homogeneous dispersion.Benefiting from these highly dispersed and ultrafine Pt NPs,the electrochemical surface area(ECSA)is improved to 142.98 m^(2)/gPt,2.25 times highe than that of the commercial counterpart(63.52 m^(2)/gPt).Furthermore,our structurally optimized catalys composite features a remarkably catalytic activity with a high half-wave potential(E_(1/2))of 0.895 V and an improved mass activity(MA)of 0.2289 A/mgPt,2.39-fold improvement compared to the commercia counterpart.In addition,orthogonal experiments were designed to identify the key process parameter for fabricating Pt/C catalysts,offering insights for scaled-up and industrial production.

燃料电池发动机电磁兼容设计技术研究

随着新能源行业的迅速发展,燃料电池发动机作为未来新能源系统的动力核心,越来越受到重视,而相较于传统的燃油、燃气发动机,燃料电池发动机在能源的来源及尾气排放等方面都具有明显的优势,但是由于燃料电池发动机匹配有高压、大功率的电气设备,如:DC/DC变换器、鼓风机、循环泵等,在运行的过程中极易产生严重的电磁干扰,严重影响整机的运行及可靠性,因此从电磁兼容的的原理及影响因素等方面进行了分析,提出了解决此类干扰的一些措施,并结合相关故障案例,进行了分析,希望对电磁兼容问题解决提供帮助。