China 
Africa 
Explore chapters and articles related to this topic
Application of Graphene Family Materials for High-Performance Batteries and Fuel Cells
Published in Ram K. Gupta, 2D Nanomaterials, 2022
Chen Shen, S. Olutunde Oyadiji
Use of Graphene on PEM/Electrolyte: As introduced in the previous section, the PEM needs to have good mechanical properties and selective permitted ability. The most commonly used PEM material includes poly(vinyl alcohol)-based composites, Nafion copolymer, and sulfonated-polyetheretherketones (SPEEK) [11]. The properties of these plastic-based materials can be modified easily by graphene micro-filler through the wet mixing method. The graphene-modified composites have better ionic conductivity and enhanced mechanical properties, which results in a higher power density and longer lifetime of the cell. Besides, graphene can also enhance PEM with optimized thermal stability and water absorption capacity, allowing the cell unit to function under various environmental conditions. Alternatively, instead of using graphene as micro-fillers to optimize the solid-state electrolytes, it can be directly used as a bulk or solid piece electrolyte. Nevertheless, the bulk/solid piece electrolyte technologies are not as mature as modifying PEM using micro-fillers.
Proton Transport Mechanisms in Nanofibers Ion Exchange Membrane
Published in Ahmad Fauzi Ismail, Nidal Hilal, Juhana Jaafar, Chris J. Wright, Nanofiber Membranes for Medical, Environmental, and Energy Applications, 2019
Nuha Awang, Ahmad Fauzi Ismail, Juhana Jaafar, Mohd Hafiz Dzarfan Othman, Mukhlis A. Rahman
Functionalized polymeric material selection is essential to improve the properties of PEM. A significant amount of research has been carried out to solve two of PEM main problems, methanol crossover and low proton conductivity. As a consequence, SPEEK has drawn attention due to its capability to curb these problems. Most of the studies carried out have been focusing on optimizing and preparing SPEEK membranes for fuel cell application and modifying SPEEK using different techniques. Nevertheless, though SPEEK membranes have proven their potential and so challenge the dominance of Nafion membrane application within the industry, there are still a few weaknesses that need to be improved, notably morphology. The exfoliated morphological structure is important in providing winding methanol routes to alleviate the methanol crossover. Hence, fabrication of the functionalized SPEEK by electrospinning is suggested since it is believed to provide exfoliated morphology. In addition, electrospinning is the best solution to develop high-performance membrane for ion exchange membranes.
Nanotechnology Impact on the Automotive Industry
Published in Kaufui V. Wong, Nanotechnology and Energy, 2017
Kaufui V. Wong, Patrick Andrew Paddon
The operation rate of platinum can be further improved by replacing conventional carbon powders in PEMFCs with dual-walled carbon nanotubes (DWNTs), which eliminates the issue of carbon particle isolation in the electrode layer. The assembly composes of an anode, cathode, and PEM and is often referred to as a membrane electrode assembly (MEA). With the use of hydrogen (H2) as fuel, it becomes oxidized in the anode, while oxygen is reduced in the cathode, generating the transfer of protons and electrons from the anode to the cathode through the PEM. Water is produced on the cathode; hence why the hydrophobic layer of carbon particles is so pertinent to ensure reactant gases can reach the catalyst. The Pt Ru/DWNT anode catalyst produced a 63% improvement in the direct methanol fuel cells (DMFCs) best performance compared to carbon black. Specific and mass activity of platinum also saw further improvement from the use of DWNTs, presumably due to the high electrical conductivity and surface area, as well as small diameter. Orienting the CNT film may also pose benefits in the nature of improved electrical conductivity due to zero energy loss when electrons transfer along the tubes opposed to across, increased gas permeability, and enhanced mass transport from superhydrophobicity [80].
Grey, blue, and green hydrogen: A comprehensive review of production methods and prospects for zero-emission energy
Published in International Journal of Green Energy, 2023
Priyanka Saha, Faysal Ahamed Akash, Shaik Muntasir Shovon, Minhaj Uddin Monir, Mohammad Tofayal Ahmed, Mohammad Forrukh Hossain Khan, Shaheen M. Sarkar, Md. Kamrul Islam, Md. Mehedi Hasan, Dai-Viet N. Vo, Azrina Abd Aziz, Md. Jafar Hossain, Rafica Akter
To get around the restrictions of ALK, Grubbs conceptualized the PEM phenomenon which was further developed by General Electric Co. in 1966 (Shiva Kumar and Himabindu 2019). PEM is alike to PEM fuel cell technique, where a sulfonated polymer membrane is applied as an electrolyte. H and DI water, which facilitates the electrochemical process, travels through the proton-conducting membrane as the ionic charge carrier. PEM generates high quality (99.999%) gases while operating at minor temperatures (30–80°C) and greater current densities (1–2 A/cm2) (Hydrogen and Oxygen) (Shiva Kumar and Himabindu 2019). This is caused by the higher surface area of Pt electrodes and lower pH of the electrolyte allow for a quicker hydrogen evolution reaction during PEM water electrolysis. Because it doesn’t utilize caustic electrolytes and has a lesser environmental impact, PEM water electrolysis is also safer than alkaline water electrolysis. Therefore, many water electrolyzer manufacturers are developing large-scale PEM water electrolyzers (up to MW) for industrial and transportation purposes. The stability of PEMWE is reported to be 60,000 hrs with insignificant loss of effectiveness and the targeted constancy is 100,000 hrs (Schmidt et al. 2017). However, the huge cost of the mechanisms, including electrode resources, current collectors, and bipolar layers, remains a significant challenge for PEM water electrolysis.
Stochastic modeling of degradation branching processes
Published in IISE Transactions, 2020
Changxi Wang, Elsayed A. Elsayed
In addition to the failure of materials, crack growth and branching degradation is one of the major causes of structure failures (Guo et al., 2018) such as the failures of concrete and fuel cell membranes (Singh et al., 2017). When the crack length or number of cracks formed reach specified values, failures occur as demonstrated in the following example. Polymer Electrolyte Membrane (PEM) fuel cells are widely used in transport applications such as electric vehicles to supply electrical energy by converting hydrogen and oxygen (air) into water. In the PEM fuel cells, the polymeric membranes that separate the electrodes allow certain protons to pass through them. It is of vital importance for the membranes to be efficient and reliable. However, the fluctuation of operating conditions poses significant durability challenges for PEM fuel cells. Figure 1(a) shows an infrared image of the failed membranes, where the bright sections correspond to a high local temperature, indicating the through-membrane leakage caused by the cracks. Figure 1(b) shows the cross-sectional view of branched membrane cracks, which causes the crossover leakage. The crack is initiated on the left-hand side and branches during its propagation to the right. The cracks grow and branch with time. The degradation of the fuel cells, which is represented by leakage amount, is related to the total length of all the crack branches.
Impact of nonuniform reactant flow rate on the performance of proton exchange membrane fuel cell stacks
Published in International Journal of Green Energy, 2020
Mingzhang Pan, Xianpan Meng, Chao Li, Jinyang Liao, Chengjie Pan
The proton exchange membrane (PEM) fuel cell is an electrochemical device for energy conversion with high efficiency, low gas emissions, low operating temperature, and quick startup and load response (Abdin, Webb, and Gray 2016; Weng, Li, and Chan 2018). A typical PEM fuel cell is composed of an anode and a cathode with a membrane in between. During cell operation, hydrogen is supplied at the anode, and the hydrogen molecules are split into protons and electrons. The protons are transported by the membranes to the cathode side, and the electrons are forced to travel through an external circuit and thus electricity is generated. The electrons travel to the cathode where they are combined with the protons and oxygen, generating water (Guo et al. 2015; Weng, Li, and Chan 2018).