Cobalt nanoparticle decorated N-doped carbons derived from a cobalt covalent organic framework for oxygen electrochemistry

Rechargeable Zinc-Air Batteries: Advances, Challenges, and Prospects

Rechargeable zinc-air batteries (Re-ZABs) are one of the most promising next-generation batteries that can hold more energy while being cost-effective and safer than existing devices. Nevertheless, zinc dendrites, non-portability, and limited charge-discharge cycles have long been obstacles to the commercialization of Re-ZABs. Over the past 30 years, milestone breakthroughs have been made in technical indicators (safety, high energy density, and long battery life), battery components (air cathode, zinc anode, and gas diffusion layer), and battery configurations (flexibility and portability), however, a comprehensive review on advanced design strategies for Re-ZABs system from multiple angles is still lacking. This review underscores the progress and strategies proposed so far to pursuit the high-efficiency Re-ZABs system, including the aspects of rechargeability (from primary to rechargeable), air cathode (from unifunctional to bifunctional), zinc anode (from dendritic to stable), electrolytes (from aqueous to non-aqueous), battery configurations (from non-portable to portable), and industrialization progress (from laboratorial to practical). Critical appraisals of the advanced modification approaches (such as surface/interface modulation, nanoconfinement catalysis, defect electrochemistry, synergistic electrocatalysis, etc.) are highlighted for cost-effective flexible Re-ZABs with good sustainability and high energy density. Finally, insights are further rendered properly for the future research directions of advanced zinc-air batteries.

Electrochemical Preparation of Recycled Self-Compacting Concrete Composite Beams and Their Application in Prefabricated Buildings

In order to solve the problems of electrochemical preparation of recycled self-compacting concrete composite beams and their application in prefabricated buildings, we need to meet the requirements of national housing industrialization and green buildings, make up for the low development capacity of prefabricated buildings, and improve the speed of housing construction and the rapid development of the construction industry. Now the prefabricated building has entered a period of rapid growth. However, the research on the construction technology of the prefabricated building is still in its infancy, and there are many difficulties and challenges in the construction. The deformation and internal force of a prefabricated residential laminated floor slab in the construction process of prestressed PK slab transportation, stacking, hoisting, and the laminated cast-in-situ layer will affect the normal use of the building. However, at present, there is less mechanical analysis of its construction process, so there is blindness in the formulation, implementation, and inspection of the construction scheme. Through the social survey of 200 people, 179 people believe that prefabricated buildings will be better than traditional buildings. Therefore, by participating in the practice of prefabricated housing engineering, the key mechanical problems in the construction of the composite floor slab of prefabricated housing are explored and found.

A doping-adsorption-pyrolysis strategy for constructing atomically dispersed cobalt sites anchored on a N-doped carbon framework as an efficient bifunctional electrocatalyst for hydrogen evolution and oxygen reduction

Atomically dispersed Co–N4 sites anchored on a N-doped carbon framework catalyst were constructed by a novel doping-adsorption-pyrolysis strategy for bifunctional electrocatalytic HER and ORR.

Screening of catalytic oxygen reduction reaction activity of 2, 9-dihalo-1, 10-phenanthroline metal complexes: The role of transition metals and halogen substitution

The sluggish kinetics of oxygen reduction reaction (ORR) restricts the employment of fuel cells, it is urgent to design ORR catalysts with excellent performance. The ORR performances of 2, 9-dihalo-1, 10-phenanthroline metal complexes (named as TM-X, X = Cl, Br, I) are comprehensively studied by the density functional theory methods. From the stability point of view, chlorine is more suitable for substitution. The adsorption free energy reveals that the liner relationship between adsorption free energy of *OOH and *OH is changed positively by the steric hindrance caused by the orthogonal TM-X structures. The Ni-Br stands out with the lowest overpotential of 0.34 V, and many other TM-X also show the promising ORR activity. Combining with the analysis of the Gibbs free energy diagrams and d-band center results, the substitution of halogen can improve the electronic structures of TM-X, thus enhancing their ORR activities and changing the ORR mechanism possibly.