Gongquan Sun

The insufficient durability of anion exchange membrane fuel cells (AEMFCs) remains a major barrier to their practical application. Water management is one of the critical factors governing AEMFC performance and durability. Insufficient hydration at the cathode catalyst layer and the membrane interface is considered to mainly restrict the durability of AEMFCs. To address this limitation, a super hydrophilic ionomer coating was directly introduced onto the membrane surface to construct a hydrophilicity-regulated, locally water-retentive interfacial region. Benefiting from the high water uptake of QPCBP-10 (381% at 20 °C and 451% at 90 °C), the coating formed a locally water-retentive gradient region at the cathode catalyst layer and the membrane interface, building up a good reaction micro-environment. The coating loading was optimized to balance interfacial humidification, kinetic polarization, and mass-transport polarization, with an optimal loading of 0.155 mg cm−2. During the durability testing at 300 mA cm−2 and 80 °C, the coated membrane electrode assembly (MEA) showed a voltage decay rate of 3.69 mV h−1, compared with 8.17 mV h−1 for the uncoated baseline MEA, corresponding to a 55% reduction. The time-normalized charge-transfer-resistance growth rate decreased from 0.0477 to 0.0187 Ω cm2 h−1. This work provides a targeted hydrophilicity-regulated interfacial engineering strategy for localized water management and improved operational durability of AEMFCs.

A Δ G _*OH guided framework maps the activity-stability landscape of Ru–N–C OER catalysts. Ru–NiN ₄ and RuIr–O3R emerge as top candidates, while operando simulations reveal *O-induced destabilization as the key durability bottleneck.

To address cathode poisoning caused by methanol crossover and insufficient durability in direct methanol fuel cells (DMFCs), a PtFeCoNiMo/C high-entropy nanoalloy (HEA) catalyst was synthesized via a one-pot solvothermal reduction method, and the effect of Mo incorporation on its structure and electrocatalytic performance was investigated. The catalyst exhibited outstanding oxygen reduction reaction (ORR) activity, delivering a half-wave potential of 0.868 V and a specific activity of 1.03 mA cmPt-2 at 0.90 V, which was 5.9 times that of commercial 20 wt.% Pt/C catalyst. After 30,000 accelerated durability test (ADT) cycles, the catalyst showed only a 10 mV loss in half-wave potential. Upon the addition 0.1 M CH3OH to the electrolyte, the methanol oxidation peak and current of PtFeCoNiMo/C were both much lower than those of commercial Pt/C. These results suggest that the introduction of a small amount of Mo is beneficial for balancing activity, methanol tolerance, and stability of Pt-based high-entropy alloy catalysts, making PtFeCoNiMo/C a promising candidates for ORR catalysis at the DMFC cathode.

The presence of carbon monoxide (CO) in crude hydrogen is a significant factor hindering the commercialization of hydrogen fuel cells. Introducing a direct CO fuel cell upstream can selectively oxidize and remove CO from crude hydrogen, thereby releasing electrical energy. The purified crude hydrogen is then fed into the downstream hydrogen fuel cell, which helps mitigate the poisoning effect on platinum (Pt) catalysts. Rhodium (Rh) and iridium (Ir) based single-atom catalysts (SACs) have demonstrated potential in the electrochemical CO oxidation reaction (COOR). However, the low density of SAC active sites (Rh metal loading −2 of CO oxidation gradually decreased, while the limiting current density gradually increased, indicating the high COOR activity on the SAC with a higher metal loading. The optimum Rh metal loading was determined to be 2.88 wt% and the limiting current density was found to be 2.4 mA cm⁻² with a mass activity of up to 4.18 A mg_Rh ⁻¹. Furthermore, a peak power density of 208.4 mW cm⁻² was achieved in a high-temperature single cell utilizing direct CO feed, thereby demonstrating a stable performance over a 22-hours period. This finding indicates a potential robust CO removal capability.

Dual-atom catalysts (DACs) based on M₁M₂–N–C have been utilised to regulate the active site of single-atom catalysts (SACs) and optimise their oxygen reduction reaction (ORR) activity.

Low‐volume power density remains a significant barrier to the portable application of direct methanol fuel cell (DMFC). Herein, a shared anode flow field (SAFF) structure is introduced in an active DMFC to reduce stack volume and improve discharge performance. The differences in discharge performance between the bi‐cell with SAFF and the bi‐cell with traditional anode flow field (TAFF), coupled with the effect of operating conditions on performance, are investigated by polarization curve, electrochemical impedance spectra, and voltage versus time curves. The results show that the SAFF structure enhances anode mass transfer, resulting in an improvement in peak power density and voltage stability of the bi‐cell compared to the TAFF structure. In addition, the bi‐cell with SAFF achieves its highest peak power density at a lower methanol concentration, alleviating the methanol crossover caused by high concentration. The SAFF structure is an attractive choice for DMFC portable applications.

The transient response of a high‐temperature proton exchange membrane fuel cell (HT‐PEMFC) is critical for control and optimization. The objective of this study is to investigate the effects of operating conditions and control parameters on the transient response of the HT‐PEMFC during load variations to optimize the operating conditions. The main causes of the voltage undershoot are investigated experimentally, and the effects of air stoichiometry, air humidity, operating temperature, and backpressure on the transient response of the HT‐PEMFC are evaluated in terms of internal resistance and voltage response. The results show that during load changes, the local gas starvation of the cell and the change in the hydration state of membrane‐electrode‐assembly may be the main cause of the voltage undershoot. The voltage drop is affected by the combination of ohmic resistance, charge transfer resistance, and mass transfer resistance. In addition, operating temperature and air stoichiometry can affect voltage drop and voltage undershoot during load changes. Proper humidification of the air can alleviate voltage undershoot problems. Increasing the backpressure can improve the transient performance of the cell, but does not alleviate the voltage undershoot problem. The study can provide guidelines for the design and control of HT‐PEMFC operating conditions.