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Proton-exchange membranes are considered the core of high-temperature proton-exchange membrane fuel cells (HT-PEMFCs) and determine the output power of the cells. However, current HT-PEMs, which are mainly doped with phosphoric acid (PA), face challenges such as low conductivity and loss of PA during cell operation. In this study, cardo poly(biphenyl indole) membranes (POXIA-QA) with quaternary ammonium salt terminals and tunable side-chain lengths were designed at the molecular level. The rational structural design enabled PA to form a continuous hydrogen-bonding network in POXIA-QA, which could be effectively immobilized and retained. The proton conductivity and activation energy patterns were found to be inconsistent with the PA doping level, suggesting that proton transportation depends not exclusively on the amount of PA but also on the PA distribution induced by the acidic spacer. The polymer membrane bearing a hexyl side chain spacer exhibited excellent proton conductivity (0.113 S cm−1 at 180 °C) and single-cell power density (1001.3 mW cm−2 at 180 °C). This study provides insights into the microphase separation, PA distribution, proton transfer, and high-temperature fuel cell performance of phosphonic acid-doped HT-PEMs with side chains and establishes structure–performance relationships. This study is expected to provide a theoretical basis and suitable candidate materials for the design of HT-PEMs. [ABSTRACT FROM AUTHOR]

The role of carbon sequestration in terrestrial ecosystems is crucial for achieving carbon neutrality. This study primarily focuses on examining the carbon storage in Shaanxi Province under different land-use scenarios. This study employed the LP-PLUS-InVEST model to explore the characteristics and spatial and temporal changes in carbon storage across four scenarios (business-as-usual (BUS), ecological protection (EPS), water–energy–food (WEF), and rural revitalization (RRS)) in Shaanxi Province. The results show that from 2000 to 2020, the carbon storage in Shaanxi Province is on a decreasing trend mainly due to the large occupation of ecological land by economic development. EPS has the largest increase in carbon storage under the four scenarios in 2030 and 2060. On the contrary, BUS has a rapid expansion of construction land, which leads to a gradual decreasing trend in carbon storage. WEF has a gradual increasing trend in carbon storage, while RRS has a trend of increasing and then slowly decreasing carbon storage. The spatial distribution trends of carbon storage in all scenarios were similar; high-carbon-reserve areas were mainly distributed in southern and central Shaanxi, which has a better ecological environment and less construction land, while low-value areas were distributed in the Central Shaanxi Plain, which has high land-use intensity. In terms of the stability of carbon reserves, the stable areas are predominantly concentrated in the Qinling Mountains, while the unstable areas are concentrated in the plain urban areas. Specifically, returning cultivated land to forest and grassland is an important initiative to promote the increase in carbon storage in Shaanxi Province. The decrease in carbon storage is mainly affected by strong urban expansion. Our study optimizes the land-use pattern according to the development needs of Shaanxi Province, and promotes the integrated development of ecological protection, food security, and economic development. Guidance is provided to promote regional carbon neutrality. [ABSTRACT FROM AUTHOR]

The design and development of new and efficient catalyst binder materials are important for improving cell performance in high‐temperature proton‐exchange membrane fuel cells (HT‐PEMFCs). In this study, a series of tetrafluorophenyl phosphonic acid−based binder materials (PF‐y‐P, y=1, 0.83, and 0.67) with rigid structures and controllable degrees of phosphonation were prepared and used in HT‐PEMFCs using the ultra‐strong acid‐catalyzed Friedel−Crafts reaction and the combined Michaelis−Arbuzov reaction. The samples exhibited high stability, low water uptake, superior proton conductivity, and cell performance. In addition, the oxygen mass transport properties of the PF‐1‐P binder were investigated using high‐temperature microelectrode electrochemical testing techniques. Compared with the phosphoric acid‐doped polybenzimidazole (PBI) binder, the O2 solubility of PF‐1‐P binder material increased by 30 % (5.36×10−6 mol cm−3) and the PF‐1‐P binder material exhibited better cell stability in HT‐PEMFCs. After 10.5 h of discharge at a constant current of 0.12 A cm−2, the MEA voltage decreased by 7.1 % and 20.8 % in case of the PF‐1‐P and PBI binders, respectively. [ABSTRACT FROM AUTHOR]