Covalent Organic Framework Fiber-Constructed Artificial Solid Electrolyte Interphase Layer: Facilitated Uniform Deposition of Li+ and Encapsulated Li Dendrite.

Due to ultrahigh theoretical capacity and ultralow redox poteneial, lithium metal is considered as a promising anode material. However, uneven lithium deposition, uncontrollable lithium dendrite formation, and fragile solid electrolyte interphase (SEI) lead to low lithium utilization, rapid capacity decay, and poor cycle performance. Herein, a robust artificial SEI film by coating the lithium surface with fibrous covalent organic framework (Fib-COF) was constructed, which effectively prevented dendrite penetration and battery short-circuits. Experimental results demonstrated that the Fib-COF-decorated batteries showcased higher Coulombic efficiency (CE), extended cycling stability, and superior electrolyte compatibility. The strong affinity of the carbonyl group in Fib-COF towards Li+ contributes to facilitating the Li+ uniform transfer and nucleation. In situ optical microscopy dynamically revealed the formation process of dendrite-free interphase under the function of Fib-COF layer. As a result, the modified Li anode demonstrated remarkable cycle stability for more than 650 h at 20 mA cm-2 and 5 mAh cm-2 in ether-based electrolyte and 1000 h at 0.5 mA cm-2 and 0.5 mAh cm-2 in carbonate-based electrolyte. The dendrite-free Fib-COF@Li electrodes endowed higher specific capacities of 650 mAh g-1 for Fib-COF@Li|S full cell after 250 cycles and 120 mAh g-1 for Fib-COF @Li|LiFePO4 full cells after 300 cycles.

The high-efficiency coupling of a Ni2+ coordinated/uncoordinated pyridine N-COF self-supporting nanofilm as an asymmetric supercapacitor.

A large-area COFTAPB-BPY film with a pore size of 3.9 nm was prepared on a gas-liquid interface by the virtue of the limiting and guiding functions of sodium dodecylbenzene sulfonate, followed by modification by Ni2+ ions with the reversible redox reaction of Ni(II/III), where Ni2+ was evidently anchored on the N in BPY. The obtained COFTAPB-BPY and Ni-COFTAPB-BPY nanofilms could avoid the inevitable aggregation and stacking of bulk COFTAPB-BPY, which facilitated a high specific capacitance of 0.26 mF cm-2 for the COFTAPB-BPY nanofilm and 0.38 mF cm-2 for the Ni-COFTAPB-BPY nanofilm at 0.001 mA cm-2. Considering the pseudocapacitance and double-layer capacitance traits of Ni-COFTAPB-BPY and COFTAPB-BPY nanofilms, the asymmetric Ni-COFTAPB-BPY//COFTAPB-BPY film supercapacitor was assembled with a symmetric COFTAPB-BPY//COFTAPB-BPY film device as a control. The asymmetric Ni-COFTAPB-BPY//COFTAPB-BPY film supercapacitor could enhance the energy density of 273.9 mW h cm-3 at 14.09 W cm-3 from 85.2 mW h cm-3 at 4.38 W cm-3 for the symmetric COFTAPB-BPY//COFTAPB-BPY film device. This work provides a new perspective on the application of self-supporting COF nanofilms as film asymmetric supercapacitors.

Life Satisfaction of Rural-To-Urban Migrants: Exploring the Influence of Socio-Demographic and Urbanisation Features in China.

Objectives: China has experienced an ongoing urbanisation that associated with spatial transformation and personal changes, which are expected to have direct or indirect impacts on migrants' health and well-being. This study aims to investigate their life satisfaction and the significant influences. Method: A quantitative research strategy was adopted, with the questionnaire survey towards 877 migrants across Hangzhou and Ningbo cities. Descriptive statistics showed migrants' life satisfaction, socio-demographic characteristics and urbanisation features. Three logistic regression models examined key factors that influenced life satisfaction. Results: Over one third of migrants were unsatisfied with their life. They mainly received education lower than high school and had an annual household income less than 60k. Comparatively, migrants, who worked in formal sectors, moved into resettlement communities and adapted to city life, tended to have higher levels of life satisfaction. Conclusion: There should be an improvement in migrants' life satisfaction. This could be achieved by building up their educational level and financial capability. Meanwhile, positive actions such as professional training are required to maximise their participation in formal sectors as well as community life.

Patterns of Living Lost? Measuring Community Participation and Other Influences on the Health of Older Migrants in China.

Community participation is a key element of active aging that promotes a new paradigm to enhance health and well-being as people age. However, social isolation is often a concern for older migrants. In this study, we aimed to investigate the current status of older migrants' community participation and assess the main influences on three forms of welfare, development, and organizational participation. We adopted a quantitative research design for this study. A questionnaire survey was completed by 1216 older migrants in 4 cities; 1105 valid responses were received, representing a response rate of around 91%. The research findings showed that the current participation of older migrants in community activities was limited. By comparison, full self-care capability and non-chronic illness positively affected general and welfare participation. Educated at primary school had a negative influence on general, development, and organizational participation, whereas knowledge of the local language was a significant predictor of general and development participation. Urban inclusion and resident friendship had positive effects on general, welfare, and development participation. The study also revealed direct influences of socioeconomic characteristics on different types of participation. Moving forward, actions are needed to maximize older migrants' participation in public events and community life.

High crystallinity Sn crystals on Ni foam: an ideal bimetallic catalyst for the electroreduction of carbon dioxide to syngas.

The investigation of highly efficient catalysts for the electrochemical reduction of carbon dioxide (ER-CO2) is the most critical challenge to commercialize conversion and utilization of CO2. Herein we propose a new and very promising catalyst, high crystallinity Sn crystals on Ni foam (Sn@f-Ni), for the electroreduction reaction of CO2 in potassium bicarbonate aqueous solution. The catalyst is fabricated in situ on a pretreated Ni foam substrate through a galvanostatic electrodeposition strategy. SEM and XRD demonstrate that high crystallinity Sn crystals, with an average size of 2-3 µm, evenly dispersed on the Ni foam support can be reproducibly obtained. Electrochemical measurements demonstrate that the Sn@f-Ni electrode at the deposition current of 15 mA exhibits superior performance in promoting the ER-CO2. Tafel measurements show that except for electrodes with a deposition current of 5 mA, the Tafel slopes of the other four electrodes are all above 100 mV dec-1, which is consistent with a rate-determining initial electron transfer to CO2 to form a surface adsorbed intermediate, a mechanism that is commonly invoked for metal electrodes. A stable composition of syngas can be obtained by electrolysis at -1.7 V potential (vs. Ag/AgCl), indicating that the Sn surface with high crystallinity conforms to the Heyrovsky-Volmer mechanism at a potential of -1.7 V. The ratio of CO and H2 generation was about 1 : 2, meaning it could be used as syngas for preparing some valuable fuels. This work provided an efficient method to convert the surplus CO2 to valuable syngas.

Pore Surface Engineering of Covalent Triazine Frameworks@MoS2 Electrocatalyst for the Hydrogen Evolution Reaction.

Electrochemical water splitting is an important strategy for the mass production of hydrogen. Development of synthesizable catalysts has always been one of the biggest obstacles to replace platinum-group catalysts. In this work, a high quality crystal polymer covalent triazine framework [CTF; Brunauer-Emmett-Teller (BET) surface area of 1562.6 m2 g-1 ] is synthesized and MoS2 nanoparticles are grown in situ into/onto the 1 D channel arrays or the external surface for electrocatalysis [hydrogen evolution reaction (HER)] . The state-of-the-art CTFs@MoS2 structure exhibits superior catalytic kinetics with an overpotential of 93 mV and Tafel slope of 43 mV dec-1 , which is improved over most other reported analogous catalysts. The inherent π-conjugated crystal channels in CTFs provides a multifunctional support for electron transmission and mass diffusion during the hydrogen evolution process. Catalytic kinetics analysis shows that the HER performance is closely correlated to the hierarchical pore parameters and aggregated thickness of MoS2 nanoparticles. This work provides an attractive and durable alternative to synthesize high activity and stable catalysts for HER.