Covalent organic framework–based porous ionomers for high-performance fuel cells

Zhang, Qingnuan; Dong, Shuda; Shao, Pengpeng; Zhu, Yuhao; Mu, Zhenjie; Sheng, Dafei; Zhang, Teng; Jiang, Xin; Shao, Ruiwen; Ren, Zhixin; Xie, Jing; Feng, Xiao; Wang, Bo

doi:10.1126/science.abm6304

Cited by 205 publications

(116 citation statements)

References 46 publications

(43 reference statements)

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“…In addition, the −SO 3 H group in Nafion can strongly adsorb and occupy the active center on the surface of Pt, reducing the activity of Pt. Thus, it is necessary to control the amount of Nafion when Nafion adsorbed on the Pt surface is used as the proton conductor in PEMFC. , …”

Section: Resultsmentioning

confidence: 99%

“…Thus, it is necessary to control the amount of Nafion when Nafion adsorbed on the Pt surface is used as the proton conductor in PEMFC. 58,59 Besides, Figure 3e shows that the peak at 687.3 eV came from the main element F signal derived from Nafion with the hydrophobic chain (−CF 2 −). 55 From the XPS characterization of the Pt surfaces before and after Nafion absorption on Pt, we can see that the signals of Pt and F vary a lot, which provides the theoretical support for Nafion absorption on the Pt surface to verify the establishment of a proton transfer channel.…”

Section: Atr-ftir and Xps Characterization Of Nafion Absorption On Th...mentioning

confidence: 99%

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Enhanced Triple-Phase Interface in PEMFC by Proton Conductor Absorption on the Pt Catalyst

Pan

Wen

Dan

et al. 2023

ACS Appl. Energy Mater.

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In a proton exchange membrane fuel cell (PEMFC), the membrane electrode assembly (MEA) is the core component and the region of the oxidation−reduction. In order to obtain a great performance, Pt with excellent catalyst efficiency is usually adopted in PEMFC as the catalyst. However, the high cost and poor durability remain the two major challenges in the application of PEMFC; thus, it is worth paying attention to enhance the utilization of the Pt catalyst and the stability of PEMFC. In this work, the Nafion array membrane with a larger specific surface and higher proton conductivity was applied to the cathode catalyst layer (CL) to prepare the ordered MEA. In order to improve the three-phase interface of the cathode CL, Nafion was adsorbed on the Pt particles as the proton conductor to expedite the proton transfer efficiency based on the principle that sulfonic acid is easily adsorbed on the Pt surface. In this case, the peak power density of PEMFC with Nafion absorption on the Pt surface is up to 843 mW cm −2 at the Pt loading of 61.4 μg cm −2 , which is much higher than that of the fuel cell without a proton conductor on the Pt catalyst in the cathode CL (710 mW cm −2 ). Besides, the durability tests show that PEMFCs with Nafion absorption on the Pt catalyst surface can work continuously for 100 h without obvious voltage attenuation, which is more stable than that of the bare Pt for 70 h. In conclusion, Nafion as the proton conductor was adsorbed on the Pt catalyst surface of the cathode CL to enhance the triple-phase interface in PEMFC, which is expected to be a universal method to prepare PEMFCs with high stability and peak power density at a low preparation cost.

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Section: Resultsmentioning

confidence: 99%

Section: Atr-ftir and Xps Characterization Of Nafion Absorption On Th...mentioning

confidence: 99%

Enhanced Triple-Phase Interface in PEMFC by Proton Conductor Absorption on the Pt Catalyst

Pan

Wen

Dan

et al. 2023

ACS Appl. Energy Mater.

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“…Finally, ionomer properties also influence MEA performance. Park et al analyzed CLs prepared from various ionomers containing different solvents [ 104 ]. They measured the thickness and contact angles of the ionomer films, tested the polarization curves, and investigated the high-frequency resistance of different samples.…”

Section: CL Structure In Meamentioning

confidence: 99%

Advances in Low Pt Loading Membrane Electrode Assembly for Proton Exchange Membrane Fuel Cells

et al. 2023

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Hydrogen has the potential to be one of the solutions that can address environmental pollution and greenhouse emissions from traditional fossil fuels. However, high costs hinder its large-scale commercialization, particularly for enabling devices such as proton exchange membrane fuel cells (PEMFCs). The precious metal Pt is indispensable in boosting the oxygen reduction reaction (ORR) in cathode electrocatalysts from the most crucial component, i.e., the membrane electrode assembly (MEA). MEAs account for a considerable amount of the entire cost of PEMFCs. To address these bottlenecks, researchers either increase Pt utilization efficiency or produce MEAs with enhanced performance but less Pt. Only a few reviews that explain the approaches are available. This review summarizes advances in designing nanocatalysts and optimizing the catalyst layer structure to achieve low-Pt loading MEAs. Different strategies and their corresponding effectiveness, e.g., performance in half-cells or MEA, are summarized and compared. Finally, future directions are discussed and proposed, aiming at affordable, highly active, and durable PEMFCs.

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“…[5] Therefore, the mass transfer resistance of oxygen plays an increasingly limited role in the electrode performance. [6] An in-depth understanding of the O2 mass transfer process in CCL is important to optimize the cell system.…”

Section: Introductionmentioning

confidence: 99%

Insights into oxygen mass transport mechanisms in high-temperature proton exchange membrane fuel cells with microelectrode

Chen

Niu

Zhang

et al. 2023

Preprint

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The mass transport of oxygen in the cathode catalyst layer of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) has a great impact on cell performance. However, some bulk average methods are unable to study the permeation properties of oxygen near the triple phase boundary of HT-PEMFCs due to the size mismatch. Here, we developed a microelectrode integrated system to quantitatively study the O2 mass transport behavior at the Pt/ binder interface under actual operating temperatures (100-180 °C). The oxygen diffusion coefficients and solubility obtained from potential-step chronoamperometry and a modified Cottrell equation follow the diffusion "ball-cage" model and the The mass transport of oxygen in the cathode catalyst layer of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) has a great impact on cell performance. However, some bulk average methods are unable to study the permeation properties of oxygen near the triple phase boundary of HT-PEMFCs due to the size mis-match. Here, we developed a microelectrode integrated system to quantitatively study the O2 mass transport behavior at the Pt/ binder interface under actual operating temperatures (100-180 °C). The oxygen diffusion co-efficients and solubility obtained from potential-step chronoamperometry and a modified Cottrell equation follow the diffusion "ball-cage" model and the dual-mode solubility model. Subsequently, molecular dynamics simulations were used to describe the key structural elements and diffusion behavior of oxygen molecules from the microscopic perspective. These results provide a scientific approach to study the mass transfer process of oxygen at the local environment, endowing with insightful strategies for future improvement and applications of HT-PEMFCs.

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Covalent organic framework–based porous ionomers for high-performance fuel cells

Cited by 205 publications

References 46 publications

Enhanced Triple-Phase Interface in PEMFC by Proton Conductor Absorption on the Pt Catalyst

Enhanced Triple-Phase Interface in PEMFC by Proton Conductor Absorption on the Pt Catalyst

Advances in Low Pt Loading Membrane Electrode Assembly for Proton Exchange Membrane Fuel Cells

Insights into oxygen mass transport mechanisms in high-temperature proton exchange membrane fuel cells with microelectrode

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