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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]

Alkaline fuel cell technology has been reinvigorated since the recent rapid development and deployment of anion exchange membranes. Without the "acid-stability" requirement in low pH environments such as that of proton exchange membrane fuel cells, a much wider range of materials including noble metals, non-noble transition metals, and even metal-free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media have been developed due to both thermodynamic and kinetic reasons. As compared to the rapidly increasing number of reports on the development of novel catalyst materials, the understanding of the reaction mechanisms of the various ORR electrocatalysts is quite insufficient, and the application and investigation in real alkaline anion exchange membrane fuel cells (AAEMFCs) is even scarcer. By reviewing the compositions, preparation methods, physiochemical properties and ORR performance of different categories of cathodic electrocatalysts that have emerged in the past few years, some common and intrinsic properties and factors that account for the superior activity of these materials may be extracted and summarized, which may further help to identify the reasons for the kinetic facility of the ORR in alkaline media. Some practical issues of utilization of the promising novel replacement materials for the state-of-the-art Pt-based cathodic electrocatalysts in AAEMFCs are pointed out. In addition to the progress on the development of novel materials with outstanding ORR activity, many and varied compositions and morphologies in one, two and three dimensions, scalable preparation technologies, low cost, and other unique properties, some feedback on the performance and especially the problems of their use as cathodes in AAEMFCs is urgently needed. Such feedback should provide guidelines for the design and manufacture of next-generation electrocatalysts and accelerate the application of AAEMFCs.

The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

Aggregation‐induced emission luminogens (AIEgens) in the second near‐infrared region (NIR‐II,1000‐1700 nm) have shown tremendous potential as theragnostic probe for tumor multimodal diagnostic imaging and combined treatment owing to their programmable optical, structural and functional properties. Herein, we presented a radionuclide 177Lu‐labeled AIEgen, 177Lu‐2TT‐oC6B dots, for NIR‐II fluorescence and SPECT/CT imaging‐guided tumor photothermal and radiopharmaceutical therapy. Intriguingly, 177Lu‐2TT‐oC6B self‐assembled into 10 nm dots, exhibited high NIR‐II fluorescence quantum yield (QY, 1.34 %) and unprecedented photothermal conversion efficiency (PCE, 70.3 %) in vitro, furtherly performed extremely long blood circulation (T1/2=52.4 h), persistent tumor accumulation and retention in tumor (NIR‐II SNR=5.56; SPECT SNR=36.59) via intravenous administration in vivo. Furthermore, upon NIR light activation and 177Lu irradiation, 177Lu‐2TT‐oC6B demonstrated great application potential in synergistic photothermal/radiopharmaceutical tumor therapy. [ABSTRACT FROM AUTHOR]

Aqueous Zn-ion batteries (AZIBs) are promising candidates for next generation energy devices owing to their intrinsic safety. However, some irreversible issues, such as dendrite growth, hydrogen evolution and parasitic reactions, seriously limit their practical application. Functional interfacial layers, as a successful solution, can efficiently enhance the performance of AZIBs. Nevertheless, how to achieve accurate in situ construction and multifunctional design of the interface layer remains a great challenge. Herein, we propose a novel and universal in situ electropolymerization strategy that induces radical polymerization via electroreduction of initiators to construct an interfacial layer on the surface of Zn foil. The in situ electropolymerization strategy strengthens the binding force between the interfacial layer and Zn substrate, which leads to high rate cycle stability. Furthermore, a bio-inspired nacre like multifunctional interface layer was constructed via the in situ electropolymerization. Inspired by the brick–mortar structures of nacre, the inorganic conductive layered MXene and organic sodium polyacrylate (PAAS) are tactfully used as the hard and soft phases to assemble an organic–inorganic hybrid interface layer onto the Zn electrode (MX/PAAS@Zn). On one hand, due to the organic–inorganic hybrid structure, the MX/PAAS@Zn exhibits excellent mechanical properties, which effectively inhibit dendrites. On the other hand, the plentiful zincophilic carboxyl functional groups can effectively adsorb the Zn2+ and promote homogeneous deposition. The multifunctional modified Zn electrodes can effectively accelerate the Zn deposition kinetics and suppress dendrites, corrosion, and hydrogen evolution side reactions. As a result, the symmetric cell using MX/PAAS@Zn exhibits stable and reversible Zn stripping/plating, such as a high transference number (tZn2+) of 0.80 and an extremely low polarization voltage of ≈75 mV for 400 h at a terrifyingly high current density of 10 mA cm−2 and 10 mA h cm−2. The MX/PAAS@Zn//α-MnO2 batteries exhibit a negligible capacity decay rate of 0.023% for 1800 cycles at 1 A g−1, and maintain a capacity retention rate of 84% over approximately 600 cycles at 0.2 A g−1. The in situ electropolymerization of a biomimetic interfacial layer represents a promising strategy for promoting the practical application of high performance aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

Breast cancer has become a huge burden with continued rise of incidence and death rate worldwide. Various methods for diagnosis and therapy of breast cancer have met the challenges of lack of complete information about the tumor location and limited therapy efficacy. Although aggregation‐induced emission luminogens (AIEgens) have shown great promise for various cancer treatment applications, they may be incompetent for deep‐seated tumor diagnosis due to the limited penetration depth. Herein, we designed and prepared a radiolabeled AIEgen‐based organic photothermal agent for bimodal PET/fluorescence imaging‐guided breast tumor photothermal therapy. The prepared multifunctional nanoparticles (68Ga‐TPA‐TTINC NPs) with NIR‐II fluorescence, gamma irradiation and photothermal conversion property could be efficiently taken up by tumor cells and induce reactive oxygen species burst in vitro, further boosting the photothermal treatment of tumor in vivo. More importantly, the nanoprobe could target and clearly visualize 4T1 tumor xenografts through PET and NIR‐II fluorescence imaging with high tumor/muscle ratio up to 4.8, which provides a promising tool and solution for breast tumor theranostics. [ABSTRACT FROM AUTHOR]