Scalable and controllable synthesis of atomic metal electrocatalysts assisted by an egg-box in alginate

Herein, a general strategy is developed to synthesize atomic metal catalysts using sustainable and earth-abundant sodium alginate (Na-Alg), a common seaweed extract, as a precursor. The “egg-box” structure in Na-Alg after ion-exchange with metal cations (Zn2+, Co2+, Ni2+, Cu2+, etc.) is the key to achieve a scalable and controllable synthesis of highly dispersed atomic metals. For instance, atomic Co, Ni and Cu have been successfully synthesized using this method. As a representative, the as-synthesized atomically dispersed Co on reduced graphene oxide (A-Co/r-GO) can reach a maximum metal loading of 3.6 wt%, showing outstanding catalytic activity and stability for the oxygen reduction reaction (ORR) with a half-wave potential (E1/2) of 0.842 V vs. RHE that is more positive than that of 20 wt% Pt/C (0.827 V vs. RHE) in alkaline solutions. The A-Co/r-GO catalyzed zinc-air batteries (ZABs) outperform Pt/C-based ZABs in the aspects of discharge voltage and specific zinc capacity, and can work robustly for more than 250 h with negligible voltage loss with refueling the Zn anode and KOH electrolyte periodically. This work opens up a new strategy for a general, practical and scalable synthesis of atomic metal catalysts at very low cost.No Full Tex

Integrated rocksalt–polyanion cathodes with excess lithium and stabilized cycling

Co- and Ni-free disordered rocksalt cathodes utilize oxygen redox to increase the energy density of lithium-ion batteries, but it is challenging to achieve good cycle life at high voltages >4.5 V (versus Li/Li+). Here we report a family of Li-excess Mn-rich cathodes that integrates rocksalt- and polyanion-type structures. Following design rules for cation filling and ordering, we demonstrate the bulk incorporation of polyanion groups into the rocksalt lattice. This integration bridges the two primary families of lithium-ion battery cathodes—layered/spinel and phosphate oxides—dramatically enhancing the cycling stability of disordered rocksalt cathodes with 4.8 V upper cut-off voltage. The cathode exhibits high gravimetric energy densities above 1,100 Wh kg−1 and >70% retention over 100 cycles. This study opens up a broad compositional space for developing battery cathodes using earth-abundant elements such as Mn and Fe

Diffusion-free Grotthuss topochemistry for high-rate and long-life proton batteries

The design of Faradaic battery electrodes that exhibit high rate capability and long cycle life equivalent to those of the electrodes of electrical double-layer capacitors is a big challenge. Here we report a strategy to fill this performance gap using the concept of Grotthuss proton conduction, in which proton transfer takes place by means of concerted cleavage and formation of O-H bonds in a hydrogen-bonding network. We show that in a hydrated Prussian blue analogue (Turnbull's blue) the abundant lattice water molecules with a contiguous hydrogen-bonding network facilitate Grotthuss proton conduction during redox reactions. When using it as a battery electrode, we find high-rate behaviours at 4,000 C (380 Ag-1, 508 mA cm(-2)), and a long cycling life of 0.73 million cycles. These results for diffusion-free Grotthuss topochemistry of protons, in contrast to orthodox battery electrochemistry, which requires ion diffusion inside electrodes, indicate a potential direction to revolutionize electrochemical energy storage for high-power applications

Research on Navigation Safety Evolution of Arctic Route Based on Entropy Theory

In recent years, with global warming, the development and utilization of the Arctic route has become possible. At present, the Arctic route navigation safety environment is the main factor that affects the passage of the Arctic route, so this paper mainly analyzes the development of the navigation safety environment of the Arctic route. First of all, using the fuzzy analytic hierarchy process to analyze the influence factors of the navigation safety of the Arctic route, the structure diagram of the navigation safety system of the Arctic route is divided. Secondly, according to the characteristics of navigation safety system of the Arctic route, entropy theory and fuzzy analytic hierarchy process are used to calculate the entropy values of navigation safety of Arctic routes, and the evolvement trend of navigation safety of Arctic routes is obtained. Finally, through the analysis of the trend of the Arctic route navigation security, some management countermeasures are put forward for the navigation safety of the Arctic route. The research results can provide reference for the development and utilization of the Arctic route

Research on Navigation Safety Evolution of Arctic Route Based on Entropy Theory

In recent years, with global warming, the development and utilization of the Arctic route has become possible. At present, the Arctic route navigation safety environment is the main factor that affects the passage of the Arctic route, so this paper mainly analyzes the development of the navigation safety environment of the Arctic route. First of all, using the fuzzy analytic hierarchy process to analyze the influence factors of the navigation safety of the Arctic route, the structure diagram of the navigation safety system of the Arctic route is divided. Secondly, according to the characteristics of navigation safety system of the Arctic route, entropy theory and fuzzy analytic hierarchy process are used to calculate the entropy values of navigation safety of Arctic routes, and the evolvement trend of navigation safety of Arctic routes is obtained. Finally, through the analysis of the trend of the Arctic route navigation security, some management countermeasures are put forward for the navigation safety of the Arctic route. The research results can provide reference for the development and utilization of the Arctic route

Enhanced Thermoelectric Performance of Indacenodithiophene-Benzothiadiazole Copolymer Containing Polar Side Chains and Single Wall Carbon Nanotubes Composites

Composite films of indacenodithiophene-bezothiadazole copolymers bearing polar side chains (P1) and single wall carbon nanotubes (SWCNTs) are found to show a competitive thermoelectric performance compared to their analogous polymers with aliphatic side chains (P2). The enhanced power factors could be attributed to the stronger interfacial interactions between the P1/SWCNTs compared to that of P2/SWCNTs containing the same ratio of SWCNTs. A maximum power factor of 161.34 μW m−1 K−2 was obtained for the composite films of P1/SWCNTs for a filler content of 50 wt%, which is higher than that of P2/SWCNTs (139.06 μW m−1 K−2, 50 wt%). Our work sheds light on the design of side-chains in efficient conjugated polymers/SWCNTs thermoelectric materials and contributes to the understanding of their thermoelectric properties

Analysis of the Relationship between Port Industry and Economic Growth Based on Cointegration Theory

The reciprocal covariance function between port Industry indicator and economic growth indicator is constructed according to time series, the cross spectral density between port industry indicator and economic growth indicator is obtained by Fourier transform after Yessentuki-Henning window truncation, and the correlation, coherence and leading lag relationship between port industry and economic growth were calculated by calculating the estimated values of mutual amplitude spectrum, coherence spectrum and phase spectrum. Then, the causality between port industry and economic growth is tested by cointegration theory, and the relationship between endogenous factors and exogenous variables is determined by impulse response and variance decomposition. The calculation results of the actual data show that the development of China’s port industry and economic growth maintain a high degree of consistency in the length of 3 to 4 years and economic growth will lead the development of the port industry 0.8 years to 1.1 years. The results of dynamic econometric analysis show that China’s port industry and economic growth are Granger reasons; China’s port industry has made a negative response to economic growth. The economic growth has made a positive response to the impact of the development of the port industry, and the response has gradually increased with the passage of time; China’s port industry and economic growth are affected by endogenous variables, and both of them affect each other in the course of development

Consistency Analysis of Port Industry Development and Chinese Economic Development

As a function in organization and management, coordination is used to adjust the interrelation of the individuals in the organization in order to achieve the ultimate goal. Coordination can make individuals groups in a whole, reduce the contradiction and conflict between each other and promote the realization of the overall goal. The research on the coordination of relationship between the port industry of China and the growth of economy plays an important guiding role for the port industry and healthy development of national economy. According to the correlation model between port industry and economic growth, the correlation factor between port industry and economic growth is extracted, and the coordination indicator system of the relationship between the port industry and economic growth is established. Then, this article makes correlation analysis of the standardization of indicators, removes the bigger indicators of correlation coefficient and eliminates the impact of the duplication of information between indicators in order to simplify the indicator evaluation system. The actual results by data calculation show that there were six obvious changes in the coordination degree of the relationship between the port industry and economic growth in China during the period from 1990 to 2014

Structure and Doping Optimization of IDT-Based Copolymers for Thermoelectrics

π-conjugated backbones play a fundamental role in determining the thermoelectric (TE) properties of organic semiconductors. Understanding the relationship between the structure–property–function can help us screen valuable materials. In this study, we designed and synthesized a series of conjugated copolymers (P1, P2, and P3) based on an indacenodithiophene (IDT) building block. A copolymer (P3) with an alternating donor–acceptor (D-A) structure exhibits a narrower band gap and higher carrier mobility, which may be due to the D-A structure that helps reduce the charge carrier transport obstacles. In the end, its power factor reaches 4.91 μW m−1 K−2 at room temperature after doping, which is superior to those of non-D-A IDT-based copolymers (P1 and P2). These results indicate that moderate adjustment of the polymer backbone is an effective way to improve the TE properties of copolymers