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The uniform and continuous nickel internal electrode is crucial in high capacity and highly reliable multi-layer ceramic capacitors (MLCCs). However, the mechanism and the key factors that affect the roughness of the electrode have not been investigated thoroughly. Thus, seeking suitable descriptors that describe the most influential element which decides the roughness is required for the logical design of the Ni paste. In this study, we analyzed the surface of nickel powders and compared their electrode roughness in the aspects of the surface carbon species on nickel nanoparticles. As the increase in the relative C–O/C–C and C=O/C–C ratios, the relative electrode roughness of C-Ni-1, C-Ni-2, C-Ni-3, and C-Ni-4 increased from 1.00, 1.29, 1.54 to 2.51. Thus, low contents of C–O and C=O on the surface of Ni particles could improve the uniformity of the electrode. This study suggests a valuable perspective to reveal the decisive component to build the optimum surface of nickel nanoparticles for uniform internal electrodes in MLCCs.

Despite their high theoretical energy density, lithium-oxygen (Li−O2) batteries suffer from limited cyclability originating from poor charging efficiency. In an effort to overcome this critical issue, a variety of catalysts have been introduced, but much room still remains for further advancement in catalyst design. By benchmarking hemoglobin in red blood cells that carry oxygen at a well-defined center of the molecular cage, herein, we report heme as an air-cathode catalyst with iron (Fe) active sites. Furthermore, the coordination of electron-withdrawing ligands, such as thiocyanate (S C N) and azide (N3), to the Fe center enhances its Lewis acidity to weaken the binding of oxygen intermediates (O2∗) towards more facile decomposition of the main discharging product (Li2O2). Density functional theory calculations and surface energy analysis of Fe coherently support the advantageous role of the ligand engineering in enhancing the reversibility of a Li−O2 battery.

In this research, environmental fate modeling (EFM) was studied to evaluate exposed lead-containing compounds in PSCs and their impact on the environment and on humans. Two major accidental situations involving the environment and exposure to compounds were considered plausible scenarios: fire (PbO) and flooding (PbI2). As a result, water systems were deemed the most vulnerable to the toxicity of exposure to lead compounds. In conclusion, the effect of various environmental and human factors should be assessed and safety standards should be established using the most conservative range among various environmental evaluation results.

The high specific capacity in excess of 200 mAh g-1 and low dependence on cobalt have enhanced the research interest on nickel-rich layered metal oxides as cathode materials for lithium-ion batteries for electric vehicles. Nonetheless, their poor cycle life and thermal stability, resulting from the occurrence of cation mixing between the transition-metal (TM) and lithium ions, are yet to be fully addressed to enable the widespread and reliable use of these materials. Here, we report a two-dimensional (2D) pyrazine-linked covalent organic framework (namely, Pyr-2D) as a coating material for nickel-rich layered cathodes to mitigate unwanted TM dissolution and interfacial reactions. The Pyr-2D coating layer, especially the 2D planar morphology and conjugated atomic configuration of Pyr-2D, protects the electrode surface effectively during cycling without sacrificing the electric conductivity of the host material. As a result, Pyr-2D-coated nickel-rich layered cathodes exhibited superior cyclability, rate performance, and thermal stability. The present study highlights the potential ability of 2D conjugated covalent organic frameworks to improve the key electrochemical properties of emerging battery electrodes.