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Oxygen reduction reaction via the two-electron pathway (2e− ORR) offers a sustainable opportunity for hydrogen peroxide (H2O2) production, but suffers from low selectivity. In this work, indium oxide with oxygen vacancies (In2O3−x) exhibits a H2O2 selectivity close to 98% at 0.6 V vs. RHE. Further, a Faradaic efficiency (FE) of around 95% at 0.4–0.6 V vs. RHE and a H2O2 productivity of 3.7 mol gcatalyst−1 h−1 are reached in a flow cell. In situ Raman spectra indicate that In2O3−x promotes the adsorption and activation of O2 and stabilizes oxygen intermediates. This work provides an insight into improving H2O2 selectivity for 2e− ORR catalysts. [ABSTRACT FROM AUTHOR]

Flexible zinc ion batteries (FZIBs) have garnered significant attention owing to their cost-effectiveness, environmental friendliness, excellent flexibility and advanced security. Nevertheless, the electrochemical performance of FZIBs, such as energy density and cycling life, has yet to be improved compared to that of conventional rigid zinc-ion batteries (ZIBs). Due to the excellent electrical conductivity and mechanical properties exhibited by advanced one or two dimensional (1D/2D) carbon materials, they are increasingly recognized to play a key role in constructing flexible electrodes and improving the capacity, energy density/power density of FZIBs. However, no review comprehensively summarizes the functions and advances of 1D/2D carbon materials in FZIBs to date. In this review, a comprehensive overview of the development background of 1D/2D carbon materials (carbon nanotubes, graphene, MXenes and carbon fiber), highlighting their great advantages and functions of applications in FZIBs is given. Detailed summaries of recent advancements and the current challenges of 1D/2D carbon materials for high-performance FZIBs along with promising strategies are provided. First, the essential requirements and challenges of FZIBs and the fundamental aspects of 1D/2D carbon materials, including the development background and the unique advantages of these 1D/2D carbon materials applied in FZIBs are summarized. Then, the latest developments of these 1D/2D materials in FZIBs, which could function as active materials, conductive networks, current collectors or Zn hosts in FZIBs are discussed. In addition, the application of 1D/2D carbon materials in separators and gel electrolytes is specially emphasized. Finally, the development prospect of 1D/2D carbon materials used in FZIBs is briefly discussed. [ABSTRACT FROM AUTHOR]

This paper deals with the effects of curing process and hygrothermal environment on the distortion behaviors of continuous carbon fiber reinforced polyamide 6 (CF/PA6) unsymmetric laminates. To accurately characterize the shape of CF/PA6 unsymmetric laminates in the water absorption process, the 3D model reconstruction with different water content is carried by combining 3D scanner and secondary development in Abaqus. A full-field displacement comparison method is proposed to calculate the equivalent thermal/moisture expansion coefficient, and the effectiveness of numerical simulation is verified. The dataset with 2816 instances is further constructed through finite element method. Through grid search and five-fold cross validation, the ANN model is trained and validated according to R 2 and MSE criterion. The well-trained ANN model builds the mapping relationship between lay-up design parameters, hygrothermal environment and the distortion parameters of unsymmetric laminates. [ABSTRACT FROM AUTHOR]

The electrocatalytic CO2 reduction reaction (CO2RR) can not only alleviate the negative effects caused by excessive CO2, but also produce the carbon-containing fuels to alleviate energy shortages. However, the reactive paths of CO2RR are relatively complicated, and the problems such as low selectivity, low current density and poor stability exist. It is urgent to develop efficient and inexpensive catalysts to promote its development. Ultra-thin materials have the advantages of large specific surface area, fully exposed active sites, accelerated kinetic mass transfer, and adjustable electronic structure. They are expected to break the bottleneck of CO2RR, thus receiving widespread attention. Here, the synthesis and application of ultra-thin materials in the past four years in electrocatalytic CO2RR to produce liquid fuels (formic acid, methanol, acetic acid) were briefly summarized. The advantages of ultra-thin materials over bulk materials and their influence on catalytic activity, selectivity and reaction paths were discussed. Also, some suggestions for future development trends, including the synthesis methodology of ultra-thin materials, their potential as supports, mechanism analysis and machine learning were put forward.

Interfacial degradation is the main reason for deterioration of mechanical properties of composites in hydrothermal environments. In this study, the effect of the interphase on water diffusion in two types of unidirectional continuous carbon fiber-reinforced polyamide 6 (CF/PA6) composites is investigated through experimental measurements, theoretical analysis, and numerical simulation. The moisture diffusion coefficient of composite at different environmental temperatures is characterized by water immersion tests for analyzing the barrier and accelerating effects of the interphase layer. Based on the experimental results, the three-phase Halpin–Tsai model is derived and validated, and then the critical diffusivity is obtained to quantify the interfacial effect during the diffusion process. To further validate the present three-phase Halpin–Tsai model, the stable and transient finite element models of moisture diffusion are developed. It is found that the critical diffusivity coefficient of the interphase for the CF/PA6 composite system is 7.31 times higher than that of the matrix.

The wide application of portable electrical equipment, aerial vehicles, smart robotics, etc. has boosted the development of advanced batteries with safety, high energy density, and environmental adaptability. Inspired by the fat layer on animal bodies, biomimetic fat is constructed as electrolytes of solid‐state zinc‐air batteries to achieve excellent cycling performance at low temperatures. Via tailored anion‐H2O interaction, the antifreezing gel electrolytes, with the multi‐performance of interface compatibility, temperature adaptability, and stable power supply simultaneously, build robust Zn|electrolyte interface, thus promoting uniform interfacial electric fields and Zn deposition. Excellent long‐term cyclability of 120 h at a high current density of 50 mA cm−2 are exhibited at 25 °C. Moreover, at −40 °C, a record‐long cycling life of 205 h at a current density as large as 10 mA cm−2 is achieved. [ABSTRACT FROM AUTHOR]

It is an urgent need to improve the depth of discharge (DOD) of Zn–air batteries (ZABs), considering that most reported ZABs with long cycle life are realized at low DOD (<1%). In this work, our solid-state ZABs achieved a long cycle life of more than 220 h at 3.2% DOD (the discharge capacity of 10 mA h cm−2 per cycle). Moreover, benefiting from excellent bifunctional oxygen electrocatalysts (Fe@BNC) and robust Zn‖electrolyte interface, the ZABs displayed a long cycle life of 120 h even at high DOD of 23.4% and large discharge capacity of 72 mA h cm−2. Additionally, the impact of Zn‖electrolyte interface on the cycle time at different DODs is analysed and discussed. The unstable interface exacerbated the dendrite growth and uneven deposition of Zn at high DOD, leading to the decay of the cycle life. The work gives insights into the mechanism of the effect of DOD on the cycle life of the batteries. [ABSTRACT FROM AUTHOR]