Voltage Decay Rate Research Articles

The Corrosion Characteristics of Graphite Coatings on Nickel Foam and Their Applications in High-Temperature Proton Exchange Membrane Fuel Cells

This study investigates the effectiveness of graphite coatings on nickel foam for use in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). Nickel foam, known for its high porosity and good conductivity, serves as an advantageous alternative to traditional flow channels but faces corrosion challenges in HT-PEMFCs, especially from phosphoric acid leakage. Graphite coatings are used as the protection layer and compared with nitride coatings. Chemical vapor deposition process parameters are first optimized for graphite growth. Corrosion polarization curves are then measured using a high-temperature phosphoric acid three-electrode system simulating HT-PEMFC conditions, followed by an analysis of the surface morphology of the samples. Subsequently, the performance and durability of the nickel foams with different coatings are evaluated after being assembled in single fuel cells. The results highlight the superior corrosion resistance of graphite coating under HT-PEMFC conditions, demonstrating its performance over other coatings. Graphite-coated foams showed a significant reduction in corrosion current, approximately 58% lower than uncoated foams and 21% lower than the TiN coated foams. In practical applications, an HT-PEMFC single cell with graphite-coated nickel foam demonstrated a current density of 763 mA/cm2 at 0.6 V under conditions of 180 oC and 2 atm H2/air. The current density is 40% higher than that of the uncoated nickel foam. The results show notable long-term durability under constant current holding tests at 160 oC. The voltage decay rate in the graphite-coated cell was 48% lower compared to the cell with uncoated nickel forms.

Topologically Close-Packed Frank-Kasper C15 Phase Intermetallic Ir Alloy Electrocatalysts Enables High-Performance Proton Exchange Membrane Water Electrolyzer.

Chemical synthesis of unconventional topologically close-packed intermetallic nanocrystals (NCs) remains a considerable challenge due to the limitation of large volume asymmetry between the components. Here, a series of unconventional intermetallic Frank-Kasper C15 phase Ir2M (M = rare earth metals La, Ce, Gd, Tb, Tm) NCs is successfully prepared via a molten-salt assisted reduction method as efficient electrocatalysts for hydrogen evolution reaction (HER). Compared to the disordered counterpart (A1-Ir2Ce), C15-Ir2Ce features higher Ir-Ce coordination number that leads to an electron-rich environment for Ir sites. The C15-Ir2Ce catalyst exhibits excellent and pH-universal HER activity and requires only 9, 16, and 27mV overpotentials to attain 10mA cm-2 in acidic, alkaline, and neutral electrolytes, respectively, representing one of the best HER electrocatalysts ever reported. In a proton exchange membrane water electrolyzer, the C15-Ir2Ce cathode achieves an industrial-scale current density of 1 A cm-2 with a remarkably low cell voltage of 1.7V at 80°C and can operate stably for 1000 h with a sluggish voltage decay rate of 50 µV h-1. Theoretical investigations reveal that the electron-rich Ir sites intensify the polarization of *H2O intermediate on C15-Ir2Ce, thus lowering the energy barrier of the water dissociation and facilitating the HER kinetics.

Toroidal Alfvén eigenmodes excited by energetic electrons in EAST low-density Ohmic plasmas

Abstract Operation in the quiescent regime with abundant trapped energetic electrons (EEs) has been achieved during the current flattop in EAST low-density Ohmic plasmas. This was facilitated by increasing the electron density to a specified level and subsequently reducing it slowly, resulting in the accumulation of a sufficient number of trapped EEs within the energy range of 150–250 keV. During the phase of decreasing electron density, toroidal Alfvén eigenmodes (TAEs) were observed to be excited by these EEs, with frequencies falling within the range of about 100–300 kHz. The experimental parameters were carefully set to satisfy the resonance conditions for TAE excitation by EEs, aligning well with predictions from ideal MHD theory. Statistical analysis indicated different density dependencies between the frequencies of TAEs and the Alfvén frequencies, due to their different radial excitation positions. The radial positions of the TAEs were found to be influenced by the energy distribution and the evolution of trapped EEs, which in turn were affected by the decay rate of electron density and loop voltage. Measurements of Hard X-rays (HXR) confirmed an energy distribution characterized by a “bump-on-tail” shape, with the TAEs observed near the energy bump. Theoretical considerations also demonstrate the possibility that the e-TAE can be driven unstable under this experiment condition even if the mode does not rotate in the electron-diamagnetic drift direction.

Is it stable for the asymmetric pressure operation of PEM water Electrolyzer?

Benefiting from the high selectivity of solid polymer membrane in transporting protons, proton exchange membrane water electrolyzer (PEMWE) have the unique capability of safely operating under asymmetric pressure between the cathode and anode (typically with the cathode under elevated pressure and the anode at ambient pressure). This capability is crucial for high-pressure hydrogen storage and transportation, as well as for rapid response to fluctuating renewable electricity. Although increased cathode pressure significantly simplifies system integration and reduce capital cost, the stability under asymmetric pressure operation has not been well studied and reported. In this work, durability tests under different pressure differences were carried out, and it was found that when the pressure difference between cathode and anode increases from zero to 3.0 MPa, the voltage decay rate increased over 15 times. The underlying reason is that the asymmetric pressure imposes additional mechanical stress on the anode catalyst layer from cathodic side, leading to increase of mass transfer resistance and irreversible structural damage, resulting in performance degradation. In view of this fact, the internal structure of the electrolyzer cell was optimized, and the uneven stress distribution and stress concentration was greatly reduced, thus mitigating performance degradation. This indicates that the stability of PEMWE is significantly affected by asymmetric pressure, additional measures need to be taken to address potential issues of catalyst layer structural damage arising from stress.

A real-time prediction method for PEMFC life under actual operating conditions

The life prediction of proton exchange membrane fuel cell (PEMFC) is one of the methods to reduce the cost of using fuel cells. This helps to solve the problem of high using costs for fuel cell vehicles, which makes it difficult to commercialize them on a large scale. However, there is still a lack of real-time life prediction methods that can be applied to fuel cell vehicles. In this article, the first step is conducting actual road vehicle life experiments, which include urban roads, suburban roads, and highways. Collect experimental data and preprocess it to obtain a dataset of actual vehicle life. The second step is to divide the output power of the fuel cell into multiple operating conditions, calculate the voltage decay rate of each operating condition, and establish a real-time prediction (RTP) model for the fuel cell life. The third step is conducting fuel cell life prediction. The results show that compared with the Pei method, the RMSE and MAPE of the proposed RTP method for fuel cell life have decreased by 21% and 14% in the long-term prediction of 100 h, and the average reduction is 41% and 35% in the short-term prediction of 10 h.

Reinforced Poly (dibenzyl-co-terphenyl piperidinium) Membranes for Highly Durable Anion-Exchange Membrane Water Electrolysis

Low-cost anion exchange membrane water electrolysis (AEMWE) is an attractive technology to solve global energy shortage and environmental problems. However, AEMWE suffers from poor performance and durability, leading to problems associated with the lack of qualified anion exchange membranes (AEMs). In this study, a reinforced membrane using PDTP (Poly(dibenzyl-co-terphenyl Piperidinium)) and PE (Polyethylen) was developed to improve performance and durability. Additionally, the effects of support layer and polymer membrane thickness on water electrolysis were observed. Due to the excellent electrochemical properties of filled PDTP, the prepared reinforced membranes exhibit excellent mechanical properties with tensile strength > 112 MPa, elongation at break > 84%, conductivity (96.3 mS cm−1), and dimensional stability (swelling). ratio < 50% at 80°C). More importantly, the AEMWE based on the reinforced membrane exhibits an outstanding current density of 4.86 A cm−2@2.0 V at 2.0 V and voltage decay rate, while simultaneously exhibiting in-situ durability of less than 1 and 2 A cm−2 for 1000 hours at 60°C. That it can be achieved. 0.02 mV h−1 and 0.1 mV h−1, respectively. This study shows that PDTP reinforced composite membrane can effectively improve AEMWE performance and durability.

Bioadhesive-Inspired Ionomer for Membrane Electrode Assembly Interface Reinforcement in Fuel Cells.

Anion exchange membrane fuel cells promise a sustainable and ecofriendly energy conversion pathway yet suffer from insufficient performance and durability. Drawing inspiration from mussel foot adhesion proteins for the first time, we herein demonstrate catechol-modified ionomers that synergistically reinforce the membrane electrode assembly interface and triple-phase boundary inside catalyst layers. The resulting ionomers present exceptional alkaline stability with only slight ionic conductivity declines after treatment in 2 M NaOH aqueous solution at 80 °C for 2500 h. Adopting catechol-modified ionomer as both anion exchange membrane and binder achieves a single-cell performance increase of 34%, and more importantly, endows fuel cell operation at a current density of 0.4 A cm-2 for over 300 h with negligible performance degradation (with a cell voltage decay rate of 0.03 mV h-1). Combining theoretical and experimental investigations, we reveal the molecular adhesion mechanism between the catechol-modified ionomer and Pt catalyst and illuminate the effect on the catalyst layer microstructure. Of fundamental interest, this bioadhesive-inspired strategy is critical to enabling knowledge-driven ionomer design and is promising for diverse membrane electrode assembly configurational applications.

Highly acid-stable high-temperature proton exchange membrane: Azide-based polymeric ionic liquids for the enhancement of amino-polybenzimidazole

Polybenzimidazole (PBI) is commonly used for high-temperature proton exchange membranes. However, it is undeniably challenging for phosphoric acid (PA)-doped PBI membranes to have both high proton conductivity and excellent long-term stability. In this study, a series of polymer ionic liquid composite PBI membranes were fabricated. These membranes are made using two azide-functional ionic liquids and amino-polybenzimidazole, adjusting the amount of the two ionic liquids. The ionic pairs offered by the ionic liquids positively impact the transportation of protons and the stability of PA through the replacement of anions. It is noteworthy that crosslinked amino-polybenzimidazole membranes containing functional polymeric ionic liquids have proton conductivity of up to 131.7 mS cm−1 at 180 °C, and the PA retention after 240 h at 160 °C under humidity-free conditions is 86.5 %. In addition, the membrane is used in membrane electrodes with hydrogen and oxygen at the anode and cathode, respectively, exhibiting a peak power density of 694.6 mW cm−2 at 160 °C. And the voltage decay rate is 0.28 mV h−1 after long-term test. The findings indicate that membranes made of functional polymeric ionic liquids crosslinked with amino-polybenzimidazoleprovide a new strategy to enhance fuel cell durability.

Realizing Superior Durability of Water Electrolyzer Using Anion Exchange Membrane with an Interstitial Alkyl Chain: From a Single Cell to Large‐Sized 1‐cell Stack

AbstractAnion exchange membrane water electrolysis (AEMWE) has gained attention as an attractive alternative to alkaline and proton exchange membrane water electrolysis (PEMWE) due to its high efficiency and low hydrogen unit cost. However, the long‐term durability of AEMWE is ≈10 times lower than that of PEMWE, which typically operates for 40 000 h. Here, a new design strategy is presented for aryl ether‐free PFPBPF‐QA anion exchange membranes with interstitial alkyl chains in the conducting groups and polymer backbone. The rationally designed PFPBPF‐4‐QA, with a suitable ion exchange capacity, shows high ionic conductivity, mechanical properties, alkaline stability, and stronger membrane‐ionomer contact properties at the catalyst layers. A single AEMWE cell using PFPBPF‐4‐QA demonstrated a voltage decay rate of 2 mV kh−1 at 1.0 A cm−2, which is significantly lower than that reported for AEMWEs and Nafion‐based PEMWEs. Additionally, a large‐sized 1‐cell AEMWE stack utilizing PFPBPF‐4‐QA with an active area of 63.6 cm2 achieved an energy conversion efficiency of 80.2% and a voltage decay rate of 1.5 mV kh−1 for 2 000 h, with over 90% of the initial efficiency maintained for over 49 095 h based on an exponential fitting calculation.

Synergistic effect of hydrogen bond and carbon coating to suppress the capacity and voltage fading in Li-Rich cathode

The voltage and capacity degradation of high-capacity Li-rich Mn-based (LRM) batteries during cycling have been a formidable barrier to their commercial application. In this study, a modified material coated with 15 nm-thick hydroxy-rich carbon layer (C-LRM) is synthesized by hydrothermal method, and C-LRM-PAA electrode is assembled by combining C-LRM with LiPAA binder. The strong hydrogen bond formed by the rich carboxyl group in LiPAA and the hydroxyl group in C-LRM makes the components of the C-LRM-PAA electrode closely connected to avoid electrode cracking, and the coating of the carbon layer avoids the cracking of the cathode particles. Consequently, this unique combination successfully inhibits transition metal dissolution, diminishes charge transfer impedance, and augments the lithium-ion diffusion coefficient, all of which contribute to suppressing the capacity and voltage attenuation. The electrochemical performance shows that after 200 cycles at 1C, the capacity retention rate increases from 40.8 % to 75.5 %, and the voltage decay rate decreases from 2.925 mV per cycle to 2.135 mV per cycle. This provides a new perspective for the electrode design of high energy density LRM batteries.

Synergistic effect of interlayered doping and surface modification to improve the performance of Li-rich manganese-based cathode materials

Li-rich manganese-based oxides (LRMOs) with high energy density have been intensively studied, but their practical use as cathode materials for lithium-ion batteries is still impeded by the shortcomings such as low initial coulombic efficiency, voltage decay and poor rate capability. To address these issues, element Nb is selected to bulk dope and simultaneously surface modify the hierarchical Li1.20Mn0.54Co0.13Ni0.13O2 spheres in this work. Synergistic effect of Nb doping and surface modification on the crystalline structure and electrochemical performance of the resultant LRMOs is characterized in detail. The results suggest that Nb5+ ions are doped into the interlayer sites within the crystals while the LiMn2O4 and LiNb3O8 double layers are coated on the primary nanoparticles. The galvanostatic charge-discharge measurements reveal that the optimal LRMO-Nb2 sample can deliver the capacities of 286 and 167 mAh g−1 at the rates of 0.1 C and 5 C, respectively, and retains a capacity of 191 mAh g−1 at 1 C rate after 200 cycles. Ex-situ XRD patterns prove that the layered structure is strongly pillared by the interlayer-doped Nb5+ during the delithiation/lithiation processes. Especially, some lithium vacancies formed around Nb5+ ions can accelerate the diffusion of Li+ ions, which was proved by DFT calculations and experimental results. Our research demonstrates that cooperating of the interlayered doping of Nb5+ with surface coating of LiNb3O8 layer can improve rate capability and cyclability of the resultant LRMOs significantly.

Investigation of Performance Degradation and Control Strategies of PEMFC under Three Typical Operating Conditions

Accelerated durability test methods exist for proton exchange membrane fuel cells. However, there is no standardized method for estimating their lifetime. Moreover, the coupling degradation mechanism under typical automotive conditions remains obscure, severely hindering durability improvement. The present study investigated the degradation behavior and the mechanism and control strategies under three typical operating conditions. The dynamic load rate should not exceed 150 mA cm−2 s−1 to ensure proper response times and voltage decay rates. The continuous runtime should not exceed 5 h to cater for longer operations with a slow rate of voltage decay. For the purge strategy during the shutdown condition, the auxiliary load purge condition had a lower voltage decay rate, which can significantly reduce the unnecessary attenuation during the shutdown. After characterization with electrochemical test methods, the degradation mechanism under three typical operating conditions was mainly manifested by the attenuation of catalytic activity and the impairment of mass transfer capacity. Furthermore, this study further clarified the quantitative relationship between degradation mechanism and performance decline, guiding the optimization of actual on-board control strategies for proton exchange membrane fuel cells.

Regulation of both Bulk and Surface Structure by W/S Co‐Doping for Li‐Rich Layered Cathodes with Remarkable Voltage and Capacity Stability

AbstractLithium‐rich layered oxides (LLOs) have gained significant attention due to their high capacity of over 250 mAh g−1, which originates from the charge compensation of oxygen anions activated under high voltage. However, the charge compensation of oxygen anions is prone to over‐oxidation, leading to serious irreversible oxygen release, surface‐interface reactions, and structural evolution. These detriments make LLOs undergo fast voltage decay and capacity fading, which have hindered their practical applications for many years. Herein, this work develops a multifunctional co‐doping strategy and constructs W─O bonds with strong bonding interaction and covalence, low bond energy Li─S bonds with non‐binding electrons near the Fermi level, and continuous and homogeneous surface spinel‐like layer induced by W/S co‐doping. Their synergistic effect significantly mitigates the irreversible oxygen release and surface‐interface reactions and improves structural stability of Li‐rich layered cathodes. Thus, the designed and prepared Co‐free Li‐rich layered cathode (Li1.232Mn0.574Ni0.191W0.003O1.995S0.005) delivers superior voltage and capacity stability. Its capacity retention after 400 cycles is as large as 86%, and its voltage decay rate from the 10th to the 400th cycle is only 0.626 mV cycle−1.

Double cross-linked 3D layered PBI proton exchange membranes for stable fuel cell performance above 200 °C

Phosphoric acid doped proton exchange membranes often experience performance degradation above 200 °C due to membrane creeping and phosphoric acid evaporation, migration, dehydration, and condensation. To address these issues, here we present gel-state polybenzimidazole membranes with double cross-linked three-dimensional layered structures via a polyphosphoric acid sol-gel process, enabling stable operation above 200 °C. These membranes, featuring proton-conducting cross-linking phosphate bridges and branched polybenzimidazole networks, effectively anchor and retain phosphoric acid molecules, prevent 96% of its dehydration and condensation, improve creep resistance, and maintain excellent proton conductivity stability. The resulting membrane, with superior through-plane proton conductivity of 0.348 S cm−1, delivers outstanding peak power densities ranging from 1.20–1.48 W cm−2 in fuel cells operated at 200-240 °C and a low voltage decay rate of only 0.27 mV h−1 over a 250-hour period at 220 °C, opening up possibilities for their direct integration with methanol steam reforming systems.

Molten-Salt-Assisted Strategy Enables High-Rate Micron-Sized Single-Crystal Li-Rich, Mn-Based Layered Oxide Cathode Materials.

Li-rich Mn-based layered oxides (LMLOs) are expected to be the most promising high-capacity cathodes for the next generation of lithium-ion batteries (LIBs). However, the poor cycling stability and kinetics performance of polycrystalline LMLOs restrict their practical applications due to the anisotropic lattice stress and crack propagation during cycling. Herein, B-doped micron-sized single-crystal Co-free LMLOs were obtained by molten-salt (LiNO3 and H3BO3)-assisted sintering. The results reveal that the low-melting-point molten salt can serve as liquid-phase media to improve the efficiency of atomic mass transfer and crystal nucleation and growth. The modified single-crystal LMLO cathodes can resist the accumulation of anisotropic stress and strain during the cycling and reduce interface side reactions, thus achieving excellent high-voltage stability and kinetics performance. The reversible specific capacity of the single crystals is 210.8 mAh g-1 at 1C with a voltage decay rate of 1.95 mV/cycle and up to 161.1 mAh g-1 at 10C with a capacity retention of 81.06% after 200 cycles.

ETFE-grafting ionomers for anion exchange membrane water electrolyzers with a current density of 11.2 A cm−2

In the quest for efficient and sustainable hydrogen production, anion exchange membrane (AEM) water electrolyzers (AEMWEs) have gained significant attention. Development of AEMs has accelerated in the past few decades while the significance of the ionomer on AEMWE performance and durability is always unrecognized. In this study, we proposed a class of electrochemically durable ionomers by introducing the piperidinium group onto the ethylene tetrafluoroethylene (ETFE) backbone using a radiation grafting technology. To avoid disruption of the conformation of the piperidinium group during the functionalization process, we grafted the piperidinium group onto the polymer backbone at the gamma position of the N-piperidinium group using trifluoromethanesulfonic acid as a catalyst. The prepared ETFE-g-poly(styryl propyl piperidinium) ionomers exhibited outstanding electrochemical properties and enhanced alkaline stability. Most notably, the corresponding AEMWEs demonstrated an impressive current density of 11.2 A cm−2 at 2.0 V under 80 °C in 1 M KOH solution. Furthermore, they were continuously operated at a current density of 0.5 A cm−2 for over 300 h with a low voltage decay rate of 0.12 mV h−1. This study offers valuable insights into the development of robust solid-state ionomers through radiation grafting, paving the way for high-performance AEMWEs.

Dual-Proton Conductor for Fuel Cells with Flexible Operational Temperature.

The properties of proton conductors determine the operating temperature range of fuel cells. Typically, phosphoric acid (PA) proton conductors exhibit excellent proton conductivity owing to their high proton dissociation and self-diffusion abilities. However, at low temperatures or high current densities, water-induced PA loss causes rapid degradation of cell performance. Maintaining efficient and stable proton conductivity within a flexible temperature range can significantly reduce the start-up temperature of PA-doped proton exchange membrane fuel cells. In this study, a dual-proton conductor composed of an organic phosphonic acid (ethylenediamine tetramethylene phosphonic acid, EDTMPA) and an inorganic PA is developed for proton exchange membranes. The proposed dual-proton conductor can operate within a flexible temperature range of 80-160 °C, benefiting from the strong interaction between EDTMPA and PA, and the enhanced proton dissociation. Fuel cells with the EDTMPA-PA dual-proton conductor showed excellent cell stability at 80 °C. In particular, under the high current density of 1.5 A cm-2 at 160 °C, the voltage decay rate of the fuel cell with the dual-proton conductor is one-thousandth of that of the fuel cell with PA-only proton conductor, indicating excellent stability.

Triptycene Branched Poly(aryl-co-aryl piperidinium) Electrolytes for Alkaline Anion Exchange Membrane Fuel Cells and Water Electrolyzers.

Alkaline polymer electrolytes (APEs) are essential materials for alkaline energy conversion devices such as anion exchange membrane fuel cells (AEMFCs) and water electrolyzers (AEMWEs). Here, we report a series of branched poly(aryl-co-aryl piperidinium) with different branching agents (triptycene: highly-rigid, three-dimensional structure; triphenylbenzene: planar, two-dimensional structure) for high-performance APEs. Among them, triptycene branched APEs showed excellent hydroxide conductivity (193.5 mS cm-1 @80 °C), alkaline stability, mechanical properties, and dimensional stability due to the formation of branched network structures, and increased free volume. AEMFCs based on triptycene-branched APEs reached promising peak power densities of 2.503 and 1.705 W cm-2 at 75/100 % and 30/30 % (anode/cathode) relative humidity, respectively. In addition, the fuel cells can run stably at a current density of 0.6 A cm-2 for 500 h with a low voltage decay rate of 46 μV h-1 . Importantly, the related AEMWE achieved unprecedented current densities of 16 A cm-2 and 14.17 A cm-2 (@2 V, 80 °C, 1 M NaOH) using precious and non-precious metal catalysts, respectively. Moreover, the AEMWE can be stably operated under 1.5 A cm-2 at 60 °C for 2000 h. The excellent results suggest that the triptycene-branched APEs are promising candidates for future AEMFC and AEMWE applications.

Triptycene Branched Poly(aryl‐co‐aryl piperidinium) Electrolytes for Alkaline Anion Exchange Membrane Fuel Cells and Water Electrolyzers

AbstractAlkaline polymer electrolytes (APEs) are essential materials for alkaline energy conversion devices such as anion exchange membrane fuel cells (AEMFCs) and water electrolyzers (AEMWEs). Here, we report a series of branched poly(aryl‐co‐aryl piperidinium) with different branching agents (triptycene: highly‐rigid, three‐dimensional structure; triphenylbenzene: planar, two‐dimensional structure) for high‐performance APEs. Among them, triptycene branched APEs showed excellent hydroxide conductivity (193.5 mS cm−1@80 °C), alkaline stability, mechanical properties, and dimensional stability due to the formation of branched network structures, and increased free volume. AEMFCs based on triptycene‐branched APEs reached promising peak power densities of 2.503 and 1.705 W cm−2 at 75/100 % and 30/30 % (anode/cathode) relative humidity, respectively. In addition, the fuel cells can run stably at a current density of 0.6 A cm−2 for 500 h with a low voltage decay rate of 46 μV h−1. Importantly, the related AEMWE achieved unprecedented current densities of 16 A cm−2 and 14.17 A cm−2 (@2 V, 80 °C, 1 M NaOH) using precious and non‐precious metal catalysts, respectively. Moreover, the AEMWE can be stably operated under 1.5 A cm−2 at 60 °C for 2000 h. The excellent results suggest that the triptycene‐branched APEs are promising candidates for future AEMFC and AEMWE applications.

Porphyrin Helical Nanochannel‐Assembled Polybenzimidazole Membranes Doped with Phosphoric Acid for Fuel Cells Operating in a Temperature Range of 25–200 °C

AbstractHigh‐temperature proton‐exchange membrane fuel cells (HT‐PEMFCs) fabricated with phosphoric acid (PA)‐doped polybenzimidazole (PBI) show apparent technical advantages. In practical automotive applications, achieving cold start‐up capability is crucial. In this work, a kind of branched block proton exchange membrane (PEM) based on PBI with a low content of porphyrin ring (&lt;1 mol.%) is reported as a branched monomer. Self‐assembly into high‐density helical nanochannels under the synergistic effect of phase separation and porphyrin π−π stacking, thus the PEM can maintain a high level of PA doping. Specifically, the PA/1.8TCPP‐BrPy‐OPBI membrane shows a proton conductivity of 0.169 and 0.071 S cm−1, as well as an H2‐O2 fuel cell peak power density of 1077 and 357 mW cm−2 at 180 and 80 °C without humidification and backpressure, respectively. The membrane electrode assembly (MEA) can exhibit good fuel cell stability, with a voltage decay rate of only 7.0 µV h−1 at 80 °C. Furthermore, it maintains a peak power density of 93% even after 150 start‐up/shut‐down cycles at 25 °C. This work expands the operating temperature range of conventional PBI membranes between 25 and 200 °C and thus provides a novel strategy for high‐performance PBI‐based HT‐PEMFCs.