Nanosized zinc oxides-based materials for electrochemical energy storage and conversion: Batteries and supercapacitors

Embedding silicon in biomass-derived porous carbon framework as high-performance anode of lithium-ion batteries

ZnO is considered to be one of the promising anode materials for lithium-ion batteries, but the poor electronic conductivity and large volume variation during lithium-ion extraction and insertion process of ZnO seriously hinders its commercial application in lithium-ion batteries (LIBs). In this study, we synthesized a novel self-supporting porous ZnO nanobelt (PZB) arrays on Zn foils, in which Zn foils can be directly used as current collectors to promote electrically connection between the active materials and the current collectors. Furthermore, the well-aligned ZnO nanobelts have a thin thickness and uniform porous structure, which endue it well improved electrochemical performance. The PZB anodes display a high areal capacity of 5.91 mAh cm-2 at current density of 0.5 mA cm-2 at room temperature, and deliver an areal capacity of 1.73 mAh cm-2 at -20 °C, indicating its excellent application potential especially at low temperatures, and it makes the porous ZnO nanobelts a practical anode material for lithium-ion batteries.

https://iopscience.iop.org/article/10.1088/1361-6528/ac08bb/pdf

A novel self-supported porous ZnO nanobelt arrays on Zn foils: excellent binder-free anode materials for LIBs.

Although organic light emitting diodes (OLEDs) can find important applications in display-related fields, it still remains a challenge to fabricate high-efficiency ultraviolet (UV) OLEDs with tunable wavelength. In this work, we demonstrate a facile method to adjust the electroluminescence (EL) peak from an inverted UV-OLED device that has zinc oxide nanowires (ZnO NWs) as an electron injection layer. The organic–inorganic interface between ZnO NWs and the 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ) emission layer employed in this work allows a reduction of the diffusion length of excitons, which further results in a hampered relaxation process of higher energy states as well as a blue shift of the EL spectrum. As a result, the emission peaks of the UV-OLED can be easily adjusted from 383 nm to 374 nm by tuning both the length of the ZnO NWs and the thickness of the TAZ emission layer. Our work reveals an important correlation between emission peaks and exciton diffusion, and presents a novel approach to fabricate high-performance UV-OLEDs with the capability of facilely modifying the emission wavelength.

/pdf/retraction-wavelength-modulation-of-zno-nanowire-based-5gmrjmx8pp.pdf

Retraction: Wavelength modulation of ZnO nanowire based organic light-emitting diodes with ultraviolet electroluminescence

Hierarchical architectures composed of nanomaterials in different forms are essential to improve the performance of lithium-ion battery (LIB) anodes. Here, we systematically studied the effects of hierarchical ZnO nanostructures on the electrochemical performance of LIBs. ZnO nanowire (NW) trunks were decorated with ZnO NWs or ZnO nanosheets (NSs) by successive hydrothermal synthesis to create hierarchical three-dimensional nanostructures. The branched ZnO NSs on the ZnO NW trunk exhibited a two-fold higher specific gravimetric capacity compared to ZnO NWs and branched ZnO NWs on ZnO NW trunks after 100 cycles of charging–discharging at 0.2C (197.4 mA g−1). The improvement in battery anode performance is attributable to the increased interfacial area between the electrodes and electrolyte, and the void space of the branched NSs that facilitates lithium ion transport and volume changes during cycling.

https://pubs.rsc.org/en/content/articlepdf/2020/ra/d0ra00372g

Hierarchical assembly of ZnO nanowire trunks decorated with ZnO nanosheets for lithium ion battery anodes

Uniform size of Si nanowires (NWs) is highly desirable to enhance the performance of Si NW-based lithium-ion batteries. To achieve a narrow size distribution of Si NWs, the formation of bulk-like Si structures such as islands and chunks needs to be inhibited during nucleation and growth of Si NWs. We developed a simple approach to control the nucleation of Si NWs via interfacial energy tuning between metal catalysts and substrates by introducing a conductive diffusion barrier. Owing to the high interfacial energy between Au and TiN, agglomeration of Au nanoparticle catalysts was restrained on a TiN layer which induced the formation of small Au nanoparticle catalysts on TiN-coated substrates. The resulting Au catalysts led to the nucleation and growth of Si NWs on the TiN layer with higher number density and direct integration of the Si NWs onto current collectors without the formation of bulk-like Si structures. The lithium-ion battery anodes based on Si NWs grown on TiN-coated current collectors showed improved specific gravimetric capacities (>30%) for various charging rates and enhanced capacity retention up to 500 cycles of charging–discharging.

/pdf/a-controlled-nucleation-and-growth-of-si-nanowires-by-using-11dbwmn4.pdf

Kenneth Crossley

Papers

Hierarchical assembly of ZnO nanowire trunks decorated with ZnO nanosheets for lithium ion battery anodes

A controlled nucleation and growth of Si nanowires by using a TiN diffusion barrier layer for lithium-ion batteries