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Abstract The conversion efficiency of a thermoelectric power generator depends on the dimensionless figure-of-merit (ZT) of the constituent thermoelectric materials, which is mainly determined by their Seebeck coefficient as well as the electrical and thermal conductivity. ZnO holds promise for thermoelectric applications, yet its use is currently limited by low electrical conductivity and high thermal conductivity. Herein, we demonstrate how thermal conductivity of ZnO can be significantly reduced by intelligently combining it with a cellulose-based Ag fabric using a one-step hydrothermal method, and how different ratios of zinc nitrate hexahydrate (ZNH) to hexamethylenetetramine (HMT) can be used to fine-tune the thermoelectric performance of the resulting composite. We show that as-prepared samples have a composite structure of Ag, Zn and O without any other impurity phases. We propose that the facet dependent crystal growth orientation, from the c-axis in (101) planes to the a-axis in (100) plane, amplify phonon scattering within the material, impeding effective heat transfer and thereby lowering overall thermal conductivity to 0.046 W/mK at room temperature for composites with a 1:1 ZNH to HMT ratio.

The stability of aqueous Zn-ion batteries (AZIBs) is detrimentally influenced by the formation of Zn dendrites and the occurrence of parasitic side reactions at the Zn metal anode (ZMA)-electrolyte interface. The strategic manipulation of the preferential crystal orientation during Zn 2+ plating serves as an essential approach to mitigate this issue. Here, Zn aspartate (Zn-Asp), an electrolyte additive for AZIBs, is introduced not only to optimize the solvation structure of Zn 2+ , but also to crucially promote preferential Zn 2+ plating on the (002) crystal plane of ZMA. As a result, both side reactions and Zn dendrites are effectively inhibited, ensuring an anode surface free of both dendrites and by-products. The implementation of Zn-Asp leads to significant enhancements in both Zn||Zn symmetric and Zn||Ti batteries, which demonstrate robust cyclability of over 3200 h and high Coulombic efficiency of 99.29%, respectively. Additionally, the Zn||NaV 3 O 8 ·1.5H 2 O full battery exhibits remarkable rate capability, realizing a high capacity of 240.77 mA h g -1 at 5 A g -1 , and retains 92.7% of its initial capacity after 1000 cycles. This research underscores the vital role of electrolyte additives in regulating the preferential crystal orientation of ZMA, thereby contributing to the development of high-performing AZIBs., (© 2023 Wiley-VCH GmbH.)

• BLK-Zr-NTA film was prepared via magnetron sputtering combined with anodization. • Bulk and surface separation of charge carriers were simultaneously enhanced. • Oxygen vacancies boosted the absorption of visible light up to 1200 nm. • BLK-Zr-NTA film exhibited superior efficiency in treating heavy metal wastewater. Photocatalytic reduction of heavy metal ions offers an eco-friendly approach to wastewater treatment. However, most photocatalysts are suffering from rapid bulk and surface recombination of photo-generated charges, as well as low utilization of visible light. Herein, the simultaneous enhancement of bulk and surface separation of photo-induced charges by combining crystallographic preferred orientation (CPO) and surface oxygen vacancies (OVs) of single crystal-like black Zr doped TiO 2 nanotube arrays film (BLK-Zr-NTAs) is reported. The CPO of BLK-Zr-NTAs along [0 0 1] direction suppressed the number of recombination centers in bulk, thus driving rapid separation/migration of photo-generated carriers from bulk to the surface. Meanwhile, the large amounts of OVs acted as electron trapping sites to inhibit the charges recombination. Besides, the introduction of OVs widened the light-absorption range, extending up to 1200 nm. The BLK-Zr-NTAs show outstanding photocatalytic performance towards Cr(VI) without using any sacrificial agents or co-catalysts, in so doing emerging as one of the best photocatalysts dedicated to Cr(VI) reduction reported so far. [ABSTRACT FROM AUTHOR]

• A hollow-anode plasma was used for the deposition of crystalline Si thin films. • Optimal H 2 concentration for fast growth of crystalline films was investigated. • Optical emission intensity ratio of the H-atom and SiH* (H αI /SiH* I) was evaluated. • Higher H αI /SiH* I ratio improved physical properties of the films. • Reducing H 2 concentration is essential for fast growth with high crystallinity. The chemical-vapor-deposition of photosensitive hydrogenated-microcrystalline-silicon (µc-Si:H) thin films with <110>-preferential orientation was optimized by altering the concentration of hydrogen within a high-density hollow-anode plasma. The µc-Si:H thin films were grown using a ratio of hydrogen (H 2) to monosilane (SiH 4) in the range of 1.25 ≤ [H 2 ]/[SiH 4 ] ≤ 35, with a gas pressure of 80 Pa. The high-density hollow-anode plasma was excited remotely in a processing space by transferring a hollow-cathode plasma via a nozzle on a partition plate, which separated the processing space from a hollow-cathode discharge space and served as an anode in an ultra-high vacuum hollow-electrode-enhanced glow-plasma transportation (HEEPT) system. The hollow-cathode plasma was excited by applying very-high-frequency (VHF, 105 MHz) power to a cathode in the hollow-cathode discharge space. The growth rate, crystalline volume fraction, and <110>-preferential crystal orientation of the films exhibited almost linear correlations with the ratio of the optical emission intensities of hydrogen atoms (H α : 656 nm) and monosilane radicals (SiH*: 414 nm) (i.e. H αI /SiH* I). Reducing the [H 2 ]/[SiH 4 ] ratio by decreasing [H 2 ] improved the growth rate, crystalline volume fraction, and <110>-preferential crystal orientation of the films. These results indicated that lower concentration of H 2 was optimal for the fast deposition of photosensitive µc-Si:H thin-films with <110>-preferential crystal orientation using the HEEPT system. The <110>-preferential crystal orientation was less dependent on the VHF power, whereas the growth rate and crystalline volume fraction increased as the VHF power was increased. This result suggested that there would be a room for faster growth with retaining <110>-preferential crystal orientation. [ABSTRACT FROM AUTHOR]

Lithium nickel manganese cobalt oxide (NMC) materials, with low cost and high energy density, are considered to be among the most promising cathode materials for Li-ion batteries (LIBs). However, several issues have hindered their further deployment, particularly for high-powered applications, including limited rate capability, capacity loss during cycling (especially at high temperatures and high voltages), and difficulty in reproducibly preparing the desired particle morphology. In this work, we have developed a robust LiNi 0.33 Mn 0.33 Co 0.33 O 2 cathode material (NMC-111) capable of high-rate performance for LIBs. Our high power NMC-111 (HP-NMC) cathode materials showed significantly enhanced electrochemical performance, relative to a commercial NMC-111 (c-NMC), with discharge capacities of 138 and 131 mAh/g at high current rates of 20 and 30 C, respectively. The material also exhibited enhanced cycling stability under both room temperature and at 50 °C. We ascribe the high performance of our material to a unique crystalline microstructure observed by electron microscopy characterization, which showed preferential orientation of the Li-diffusing channels radially outward. This HP-NMC material achieved one of the highest performance metrics among NMC materials reported to date, especially for high-powered electric vehicles.