碱性电解水制氢技术（Alkaline Water Electrolysis，ALK）可用于大规模可再生电力储存，是解决离网电力存储、推动氢能产业发展的关键手段。为了进一步拓宽碱性电解水制氢的工作电流密度区间和负载范围，推动该技术的进一步发展，需要明确自支撑电极的设计策略、单元反应传递机理和耦合机制，以及ALK系统各部件的物质流、能量流匹配和稳动态响应特性。本文采用实验测试、动力学计算和数值模拟相结合的研究方法开展ALK自支撑电极构筑、单元反应特性和系统稳动态运行规律研究。ALK电极的高过电位损失限制了其在大电流密度区间的应用。本文采用动态氢气泡模板法电沉积法可控制备了不同分层多孔形貌的自支撑电极，在提高反应活性面积的基础上进一步担载活性物质，通过实验分析了电极构型对离子传递和催化活性的影响规律。其次利用氧化铈掺杂调节局部电子分布结构与电解质/电极界面优化相结合的策略，将NiFexCe1-x活性物质一步沉积在自支撑多孔骨架结构上，实现60℃时6.0 M KOH溶液中1500 mA/cm2电流密度下213 mV超低析氧过电位，并将传统镍铁基电极在室温强碱500 mA/cm2电流密度下的运行寿命提高2.5倍。通过密度泛函理论与实验测试结合的手段，揭示了Ce掺杂对OER基元反应动力学的促进作用和析氧过程界面重构现象对稳定性的影响机制。ALK单元的反应特性是阴阳极电化学反应、离子传递和传质传热综合影响的宏观表现。为阐明ALK单元不同工况下的性能限制因素，本文通过独立测量单电极反应动力学、隔膜离子传递面电阻和全水电解单元的电化学特性，识别并提取关键电化学参数，构建考虑电极本征动力学参数与隔膜物化特性的机理性电解单元非等温多场耦合模型。研究表明高电流密度下（＞1.5 A/cm2）欧姆过电位贡献了50%以上电压损失，通过合理设计运行工况可有效降低1 K进出口温差。ALK制氢系统的稳动态特性影响与可再生电力连接时的储能效率，其中冷启动速度和氧中氢含量（Hydrogen To Oxygen，HTO）是衡量ALK系统在波动电力下的启停灵活性和安全性的关键指标。本文讨论了ALK热惯性和HTO的主要成因，并在此基础上构建考虑实际物理/电化学过程的碱性电解制氢系统模型，提出利用50 A/min电流斜坡加载与外部辅助加热结合的冷启动策略，实现最短为43.3 min的安全启动。相较于无外部加热的启动过程，启动能耗可降低4.2%。
Alkaline Water Electrolysis (ALK) can be used for large-scale renewable power storage, which is a key means to solve the problem of off-grid power storage and promote the development of hydrogen energy industry. In order to further broaden the operating current density interval and load range of alkaline water electrolysis for hydrogen production, and to promote the further development of this technology, it is necessary to clarify the design strategy of the self-supporting electrode, the unit reaction transfer mechanism and the coupling mechanism, as well as the matching of material and energy flows and the steady dynamic response characteristics of each component of the ALK system. In this paper, a combination of experimental tests, kinetic calculations and numerical simulations is used to carry out the study of ALK self-supporting electrode construction, cell reaction characteristics and system steady dynamic operating principles. The high overpotential loss of ALK electrode limits its application in the high current density range. In this paper, self-supported electrodes with different layered porous morphologies were prepared by dynamic hydrogen bubble template electrodeposition method, and further loaded with active substances on the basis of improving the reactive area, and the influence of the electrode configuration on ion transfer and catalytic activity was analyzed experimentally. Secondly, a strategy combining cerium oxide doping to regulate the local electron distribution structure and electrolyte/electrode interface optimization was utilized to deposit NiFexCe1-x active substances onto the self-supported porous skeleton structure in one step, and the effect of Ce doping on the reaction kinetics of the OER primitive was revealed using a combination of density-functional theory and experimental tests to achieve the reaction kinetics of the OER primitive at 60 ℃ in 6.0 M KOH solution at 1500 mA/cm2 current density at an ultra-low oxygen precipitation overpotential of 213 mV, and improved the operating life of conventional NiFe-based electrodes at 500 mA/cm2 current density in strong base at room temperature by a factor of 2.5. The reaction characteristics of the ALK unit are the macro-performances of the combined effects of cathode and anode electrochemical reactions, ion transfer as well as mass and heat transfer. In order to elucidate the performance limiting factors of ALK units under different operating conditions, this paper identifies and extracts key electrochemical parameters by independently measuring the reaction kinetics of a single electrode, the ionic transfer surface resistance of the diaphragm and the electrochemical characteristics of the overall water electrolysis unit, and constructs a non-isothermal coupling model of a mechanistic electrolysis cell considering the intrinsic kinetics of the electrodes and the physical and chemical properties of the diaphragm, so as to clarify the evolution patterns of the over-potential distributions and heat transfer characteristics under different operating conditions and to guide the evolution of the electrochemical characteristics of the ALK unit. The evolution of overpotential distribution and heat transfer characteristics under different operating conditions is clarified to guide the design and performance optimization of the electrolysis unit.It is shown that the ohmic overpotential contributes more than 50% of the voltage loss at high current density(>1.5 A/cm2),and the temperature difference between the import and export of 1K can be effectively reduced by rationally designing operating conditions. The steady state characteristics of the ALK hydrogen generation system affect the energy storage efficiency when connected to renewable power, among which the cold start speed and Hydrogen To Oxygen (HTO) are the key indexes to measure the start/stop flexibility and safety of the ALK system under fluctuating power. In this paper, the main causes of ALK thermal inertia and HTO are discussed, and on this basis, a model of alkaline electrolytic hydrogen production system considering actual physical/electrochemical processes is constructed, and a cold-start strategy utilizing 50 A/min current ramp loading combined with external auxiliary heating is proposed to achieve a safe startup with a minimum duration of 43.3 min. Compared with the startup process without external heating, the startup energy consumption can be reduced by 4.2%.
