Article
Green & Sustainable Science & Technology
Kai Meng, Ben Chen, Haoran Zhou, Wenshang Chen, Zhengkai Tu
Summary: Improving and mitigating degradation of hydrogen-oxygen proton exchange membrane fuel cells (PEMFCs) are crucial for accelerating the practical application of clean energy and alleviating the energy crisis. In this study, a PEMFC with an active area of 25 cm2 was designed using printed circuit board technology for high-resolution current density mapping. The uneven distribution of local current density under dynamic loading and its influence on performance degradation were further analyzed. The results show that membrane dehydration, gas starvation, and combined effects of gas starvation contribute to the uneven density distribution. Oxygen starvation causes more severe uneven density distribution than hydrogen starvation, with the lowest current density concentrated near the cathode outlet. Moreover, the uneven distribution of local current density leads to significant performance degradation, including a decrease in electrochemical active surface area and an increase in charge transfer resistance.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Energy & Fuels
Yang Liu, Junjie Zhao, Zhengkai Tu, Siew Hwa Chan
Summary: Investigating the dynamic characteristics of PEMFCs and finding effective strategies to improve performance is crucial. This study proposes the integration of a recirculation subsystem and obstacle devices to alleviate gas starvation and enhance mass transfer. The findings show that accumulated liquid water causes blockage in gas transport channels, and cathode recirculation significantly improves cell performance. However, excessively high pump speeds can lead to voltage undershoot. The use of exhaust gas recirculation also proves effective in addressing gas starvation and water flooding issues.
Article
Chemistry, Physical
Yameng Wang, Jianhua Liao, Zheng Li, Buke Wu, Jialu Lou, Lin Zeng, Tianshou Zhao
Summary: This study investigates the use of a composite catalyst with an oxygen evolution reaction catalyst in the anode of proton exchange membrane fuel cells to alleviate the corrosion and performance degradation caused by voltage reversal induced by hydrogen starvation. The results show that the composite catalyst with high metal loading effectively reduces the damage to the anode catalyst layer during the voltage reversal process, resulting in improved performance and longer reversal time.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Electrochemistry
Wei Yan, Shang Li, Kuangwei Cheng, Pengtao Huang, Mike Szesny, Ulrich Misz, Wei Guo, Minhua Shao, Mu Pan
Summary: In this paper, a long-term durability test was conducted on a low Pt-loading fuel cell stack, and the performance of the membrane electrode assembly (MEA) before and after the test was analyzed. The degradation of MEA performance was mainly caused by the agglomeration and loss of Pt nanoparticles in the cathode catalyst.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Shikun Zhou, Gongnan Xie, Haibao Hu, Meng Ni
Summary: Proton exchange membrane fuel cells (PEMFCs) are clean and efficient power sources. The proposed new gas diffusion layer (GDL) with non-uniform distribution of PTFE effectively removes water from the catalyst layer (CL), improving fuel cell performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Kai Meng, Ben Chen, Haoran Zhou, Jun Shen, Zhengkai Tu
Summary: This study experimentally investigated the voltage response characteristics of hydrogen-oxygen proton exchange membrane fuel cells (PEMFC) under different degrees of hydrogen and oxygen starvation. It was found that hydrogen starvation had a more significant impact on the cell, while increasing the working temperature effectively alleviated this degradation phenomenon.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Guanghua Yang, Qihao Deng, Yu Zhou, Wenshang Chen, Ben Chen
Summary: This study investigates the dynamic response and water-gases transfer characteristics in purging stage of proton exchange membrane fuel cells (PEMFC) with dead-ended anode (DEA) operation. The experimental results show that DEA operation poses a severe threat to the PEMFC performance, but the purging stage allows it to recover. Lower operating current density and higher operating pressure can alleviate performance degradation and voltage undershoot.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Chemistry, Analytical
Rui Jiao Yu, Hang Guo, Hao Chen, Fang Ye
Summary: Porosity is a key parameter affecting the performance of gas diffusion layer in fuel cells. Non-uniform distribution of porosity can better simulate real structure and change cell performance. An optimized three-segment distribution of porosity in anode and cathode sides along three directions at different voltages was explored using a 3D, two-phase agglomerate model, and the reasons for these results at 0.2V, 0.6V and 0.8V were analyzed. The results show that as voltage increases, the average optimal porosity decreases and the porosity increases from inlet to outlet and along width direction. The reaction rate is influenced by reactant content and charge transfer at different regions depending on the voltage.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
L. Padilla Urbina, J. Liu, N. Semagina, M. Secanell
Summary: Inkjet printing is a feasible technique for the fabrication of electrode in unitized regenerative fuel cells (URFCs) and the study of optimal ionomer and catalyst loading. A physical mixture of Pt, IrOx, and Nafion ionomer was directly inkjet printed on a Nafion membrane to create bifunctional oxygen electrodes with varying loading for a URFC. The results show that the optimal electrode requires low ionomer loading and significantly less IrOx catalyst than platinum.
JOURNAL OF POWER SOURCES
(2023)
Article
Environmental Sciences
Asif Jamil, Sikander Rafiq, Tanveer Iqbal, Hafiza Aroosa Aslam Khan, Haris Mahmood Khan, Babar Azeem, M. Z. Mustafa, Abdulkader S. Hanbazazah
Summary: Fuel cells are environmentally friendly technology with high efficiency and economic advantages. Proton exchange membranes, especially for hydrogen fuel cells, have great potential but face challenges in terms of cost and degradation of proton exchange capacity over time.
Article
Energy & Fuels
Xiyuan Zhang, Bowen Wang, Yifan Xu, Lizhen Wu, Fan Zhang, Shaoqing He, Xiaosong Zhang, Kui Jiao
Summary: Proton exchange membrane electrolysis cell (PEMEC) is a promising option for hydrogen production. This study developed a comprehensive model to investigate the dynamic response of a PEMEC stack with cooling channels under variable operating conditions. The results suggest that, in addition to optimizing material parameters, considering the relationship between actual operating conditions, heat accumulation, and coolant flow is crucial.
Article
Thermodynamics
Yi Li, Fang Yuan, Rengang Weng, Fang Xi, Wei Liu
Summary: The porosity distribution in the gas diffusion layer significantly impacts cell performance. An optimized three-dimensional nonuniform porosity distribution is proposed to increase current density and power density. Different design schemes are evaluated, with the optimized porosity distribution showing the best performance.
Article
Engineering, Environmental
Qianqian Wang, Fumin Tang, Bing Li, Haifeng Dai, Jim P. Zheng, Cunman Zhang, Pingwen Ming
Summary: In this study, the thermal transient of the cathode catalyst layer (CCL) inside the proton exchange membrane fuel cell (PEMFC) under dynamic loading was investigated. The effects of current load, operating temperature, and channel to rib width ratio on the CCL temperature were systematically studied. It was found that there is an overshoot phenomenon in the CCL temperature when the current rapidly changes. This overshoot amplitude first increases and then decreases with the rise of the step current density. The loading time and operating temperature also have significant effects on the temperature overshoot. Additionally, the channel to rib width ratio affects the temperature fluctuation in different CCL regions.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Energy & Fuels
Yi Tong Li, Hang Guo, Fang Ye
Summary: The uneven distribution of oxygen concentration along the flow channel direction in a fuel cell can be improved by using a gradient decreasing distribution of platinum loading. Increasing the segment number can enhance the uniformity of temperature and oxygen concentration distributions in the cathode catalyst layer, but it is unfavorable for cell performance improvement. Increasing the segment length near the inlet area can improve the cell performance, but it may affect the uniformity of temperature distribution.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Chemistry, Physical
Ye Peng, Ja-Yeon Choi, Liliang Tian, Kyoung Bai, Yi Zhang, Dongchu Chen, Jianhuang Zeng, Dustin Banham
Summary: The distribution of platinum group metal (PGM) nanoparticle catalysts in the carbon support significantly affects the catalyst's performance. The placement of Pt either on the outer surface or within the pores of the carbon results in different activity and performance at high current densities. To gain further insight into the catalyst's properties, a relationship between Pt distribution and relative humidity (RH) tolerance is explored. This work provides valuable information for MEA designers in selecting catalysts for specific applications.
JOURNAL OF POWER SOURCES
(2022)
Article
Energy & Fuels
Shitong Fang, Houfan Du, Tao Yan, Keyu Chen, Zhiyuan Li, Xiaoqing Ma, Zhihui Lai, Shengxi Zhou
Summary: This paper proposes a new type of nonlinear VIV energy harvester (ANVEH) that compensates for the decrease in peak energy output at low wind speeds by introducing an auxiliary structure. Theoretical and experimental results show that ANVEH performs better than traditional nonlinear VIV energy harvesters under various system parameter variations.
Article
Energy & Fuels
Wei Jiang, Shuo Zhang, Teng Wang, Yufei Zhang, Aimin Sha, Jingjing Xiao, Dongdong Yuan
Summary: A standardized method was developed to evaluate the availability of solar energy resources in road areas, which combined the Analytic Hierarchy Process (AHP) and the Geographic Information System (GIS). By analyzing critical factors and using a multi-indicator evaluation method, the method accurately evaluated the utilization of solar energy resources and guided the optimal location selection for road photovoltaic (PV) projects. The results provided guidance for the application of road PV projects and site selection for route corridors worldwide, promoting the integration of transportation and energy.
Article
Energy & Fuels
Chang Liu, Jacob A. Wrubel, Elliot Padgett, Guido Bender
Summary: The study investigates the effects of coating defects on the performance of the anode porous transport layer (PTL) in water electrolyzers. The results show that an increasing fraction of uncoated regions on the PTL leads to decreased cell performance, with continuous uncoated regions having a more severe impact compared to multiple thin uncoated strips.
Article
Energy & Fuels
Marcos Tostado-Veliz, Xiaolong Jin, Rohit Bhakar, Francisco Jurado
Summary: In this paper, a coordinated charging price mechanism for clusters of parking lots is proposed. The research shows that enabling vehicle-to-grid characteristics can bring significant economic benefits for users and the cluster coordinator, and vehicle-to-grid impacts noticeably on the risk-averse character of the uncertainty-aware strategies. The developed pricing mechanism can reduce the cost for users, avoiding to directly translate the energy cost to charging points.
Article
Energy & Fuels
Duan Kang
Summary: Building an energy superpower is a key strategy for China and a long-term goal for other countries. This study proposes an evaluation system and index for measuring energy superpower, and finds that China has significantly improved its ranking over the past 21 years, surpassing other countries.
Article
Energy & Fuels
Fucheng Deng, Yifei Wang, Xiaosen Li, Gang Li, Yi Wang, Bin Huang
Summary: This study investigated the synergistic blockage mechanism of sand and hydrate in gravel filling layer and the evolution of permeability in the layer. Experimental models and modified permeability models were established to analyze the effects of sand particles and hydrate formation on permeability. The study provided valuable insights for the safe and efficient exploitation of hydrate reservoirs.
Article
Energy & Fuels
Hao Wang, Xiwen Chen, Natan Vital, Edward Duffy, Abolfazl Razi
Summary: This study proposes a HVAC energy optimization model based on deep reinforcement learning algorithm. It achieves 37% energy savings and ensures thermal comfort for open office buildings. The model has a low complexity, uses a few controllable factors, and has a short training time with good generalizability.
Article
Energy & Fuels
Moyue Cong, Yongzhuo Gao, Weidong Wang, Long He, Xiwang Mao, Yi Long, Wei Dong
Summary: This study introduces a multi-strategy ultra-wideband energy harvesting device that achieves high power output without the need for external power input. By utilizing asymmetry, stagger array, magnetic coupling, and nonlinearity strategies, the device maintains a stable output voltage and high power density output at non-resonant frequencies. Temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the device.
Article
Energy & Fuels
Tianshu Dong, Xiudong Duan, Yuanyuan Huang, Danji Huang, Yingdong Luo, Ziyu Liu, Xiaomeng Ai, Jiakun Fang, Chaolong Song
Summary: Electrochemical water splitting is crucial for hydrogen production, and improving the hydrogen separation rate from the electrode is essential for enhancing water electrolyzer performance. However, issues such as air bubble adhesion to the electrode plate hinder the process. Therefore, a methodology to investigate the two-phase flow within the electrolyzer is in high demand. This study proposes using a microfluidic system as a simulator for the electrolyzer and optimizing the two-phase flow by manipulating the micro-structure of the flow.
Article
Energy & Fuels
Shuo Han, Yifan Yuan, Mengjiao He, Ziwen Zhao, Beibei Xu, Diyi Chen, Jakub Jurasz
Summary: Giving full play to the flexibility of hydropower and integrating more variable renewable energy is of great significance for accelerating the transformation of China's power energy system. This study proposes a novel day-ahead scheduling model that considers the flexibility limited by irregular vibration zones (VZs) and the probability of flexibility shortage in a hydropower-variable renewable energy hybrid generation system. The model is applied to a real hydropower station and effectively improves the flexibility supply capacity of hydropower, especially during heavy load demand in flood season.
Article
Energy & Fuels
Zhen Wang, Kangqi Fan, Shizhong Zhao, Shuxin Wu, Xuan Zhang, Kangjia Zhai, Zhiqi Li, Hua He
Summary: This study developed a high-performance rotary energy harvester (AI-REH) inspired by archery, which efficiently accumulates and releases ultralow-frequency vibration energy. By utilizing a magnetic coupling strategy and an accumulator spring, the AI-REH achieves significantly accelerated rotor speeds and enhanced electric outputs.
Article
Energy & Fuels
Yi Yang, Qianyi Xing, Kang Wang, Caihong Li, Jianzhou Wang, Xiaojia Huang
Summary: In this study, a novel hybrid Quantile Regression (QR) model is proposed for Probabilistic Load Forecasting (PLF). The model integrates causal dilated convolution, residual connection, and Bidirectional Long Short-Term Memory (BiLSTM) for multi-scale feature extraction. In addition, a Combined Probabilistic Load Forecasting System (CPLFS) is proposed to overcome the inherent flaws of relying on a single model. Simulation results show that the hybrid QR outperforms traditional models and CPLFS exceeds the best benchmarks in terms of prediction accuracy and stability.
Article
Energy & Fuels
Wen-Jiang Zou, Young-Bae Kim, Seunghun Jung
Summary: This paper proposes a dynamic prediction model for capacity fade in vanadium redox flow batteries (VRFBs). The model accurately predicts changes in electrolyte volume and capacity fade, enhancing the competitiveness of VRFBs in energy storage applications.
Article
Energy & Fuels
Yuechao Ma, Shengtie Wang, Guangchen Liu, Guizhen Tian, Jianwei Zhang, Ruiming Liu
Summary: This paper focuses on the balance of state of charge (SOC) among multiple battery energy storage units (MBESUs) and bus voltage balance in an islanded bipolar DC microgrid. A SOC automatic balancing strategy is proposed considering the energy flow relationship and utilizing the adaptive virtual resistance algorithm. The simulation results demonstrate the effectiveness of the proposed strategy in achieving SOC balancing and decreasing bus voltage unbalance.
Article
Energy & Fuels
Raad Z. Homod, Basil Sh. Munahi, Hayder Ibrahim Mohammed, Musatafa Abbas Abbood Albadr, Aissa Abderrahmane, Jasim M. Mahdi, Mohamed Bechir Ben Hamida, Bilal Naji Alhasnawi, A. S. Albahri, Hussein Togun, Umar F. Alqsair, Zaher Mundher Yaseen
Summary: In this study, the control problem of the multiple-boiler system (MBS) is formulated as a dynamic Markov decision process and a deep clustering reinforcement learning approach is applied to obtain the optimal control policy. The proposed strategy, based on bang-bang action, shows superior response and achieves more than 32% energy saving compared to conventional fixed parameter controllers under dynamic indoor/outdoor actual conditions.