Tailoring Pore Structures of 3D Printed Cellular High-Loading Cathodes for Advanced Rechargeable Zinc-Ion Batteries.

Developing high-loading cathodes with superior electrochemical performance is desirable but challenging in aqueous zinc-ion batteries (ZIBs) for commercialization. Advanced 3D printing of cellular and hierarchical porous cathodes with high mass loading for superior ZIBs is explored here. To obtain a high-performance 3D printable ink, a composite material of iron vanadate and reduced holey graphene oxide is synthesized as the ink component. A cellular cathode with hierarchical porous architecture for aqueous ZIBs is then designed and fabricated by 3D printing for the first time. The unique structures of 3D printed composite cathode provide interpenetrating transmission paths as well as channels for electrons and ions. 3D printed cathodes with high mass loading over 10 mg cm-2 exhibit a high specific capacity of 344.8 mAh g-1 at 0.1 A g-1 and deliver outstanding cycling stability over 650 cycles at 2 A g-1 . In addition, the printing strategy enables the ease increase in mass loading up to 24.4 mg cm-2 , where a remarkably high areal capacity of 7.04 mAh cm-2 is reached. The superior electrochemical performance paves the new way to design the state-of-the-art cathodes for ZIBs.

Direct Ink Writing of Li1.3 Al0.3 Ti1.7 (PO4 )3 -Based Solid-State Electrolytes with Customized Shapes and Remarkable Electrochemical Behaviors.

All-solid-state lithium batteries have received extensive attention due to their high safety and promising energy density and are considered as the next-generation electrochemical energy storage system. However, exploring solid-state electrolytes in customized geometries without sacrificing the ionic transport is significant yet challenging. Herein, various 3D printable Li1.3 Al0.3 Ti1.7 (PO4 )3 (LATP)-based inks are developed to construct ceramic and hybrid solid-state electrolytes with arbitrary shapes as well as high conductivities. The obtained inks show suitable rheological behaviors and can be successfully extruded into solid-state electrolytes using the direct ink writing (DIW) method. As-printed free-standing LATP ceramic solid-state electrolytes deliver high ionic conductivity up to 4.24 × 10-4  S cm-1 and different shapes such as "L", "T," and "+" can be easily realized without sacrificing high ionic transport properties. Moreover, using this printing method, LATP-based hybrid solid-state electrolytes can be directly printed on LiFePO4 cathodes for solid-state lithium batteries, where a high discharge capacity of 150 mAh g-1 at 0.5 C is obtained. The DIW strategy for solid-state electrolytes demonstrates a new way toward advanced solid-state energy storage with the high ionic transport and customized manufacturing ability.

One-pot synthesis of in-situ carbon-coated Fe3O4 as a long-life lithium-ion battery anode.

Fe3O4 has been regarded as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity, low cost, and environmental friendliness. In this work, we present a one-pot reducing-composite-hydroxide-mediated (R-CHM) method to synthesize in situ carbon-coated Fe3O4 (Fe3O4@C) at 280 °C using Fe(NO3)3 · 9H2O and PEG800 as raw materials and NaOH/KOH as the medium. The as-prepared Fe3O4 octahedron has an average size of 100 nm in diameter, covered by a carbon layer with a thickness of 3 nm, as revealed by FESEM and HRTEM images. When used as anode materials in LIBs, Fe3O4@C exhibited an outstanding rate capability (1006, 918, 825, 737, 622, 455 and 317 mAh g-1 at 0.1, 0.2, 0.5, 0.8, 1.0, 1.5 and 2.0 A g-1). Moreover, it presented an excellent cycling stability, with a retained capacity of 261 mAh g-1 after 800 cycles under an extremely high specific current density of 2.0 A g-1. Such results indicate that Fe3O4@C can provide a new route into the development of long-life electrodes for future rechargeable LIBs. Importantly, the R-CHM developed in our work can be extended for the synthesis of other carbon-coated electrodes for LIBs and functional nanostructures for broader applications.

Multi-Channel Engineering of 3D Printed Zincophilic Anodes for Ultrahigh-Capacity and Dendrite-Free Quasi-Solid-State Zinc-Ion Microbatteries.

Zinc-ion microbatteries (ZIMBs) are regarded as one of most promising miniaturized energy storage candidates owing to their high safety, compatible device size, superior energy density, and cost efficiency. Nevertheless, the zinc dendrite growth during charging/discharging and the inflexible device manufacturing approach seriously restrict practical applications of ZIMBs. Herein, we report a unique material extrusion 3D printing approach with reinforced zincophilic anodes for ultrahigh-capacity and dendrite-free quasi-solid-state ZIMBs. A 3D printed N-doped hollow carbon nanotube (3DP-NHC) multichannel host is rationally designed for desirable dendrite-free zinc anodes. Favorable structural metrics of 3DP-NHC hosts with abundant porous channels and high zincophilic active sites enhance the ion diffusion rate and facilitate uniform zinc deposition behavior. Rapid zinc-ion migration is predicted through molecular dynamics, and zinc dendrite growth is significantly suppressed with homogeneous zinc-ion deposition, as observed by in situ optical microscopy. 3D printed symmetric zinc cells exhibit an ultralow polarization potential, a glorious rate performance, and a stable charging/discharging process. Accordingly, 3D printed quasi-solid-state ZIMBs achieve an outstanding device capacity of 11.9 mA h cm-2 at 0.3 mA cm-2 and superior cycling stability. These results reveal a feasible approach to effectively restrain zinc dendrite growth and achieve high performance for state-of-the-art miniaturized energy storage devices.

[The study of ultra-fine diamond powder used in magnetic head polishing slurry].

In the present paper, atomic absorption spectrometry(AAS), inductively-coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and laser Raman spectroscopy (RM) were employed to study the commercial ultra-fine diamond powders prepared by the static pressure-catalyst method and used in magnetic head polishing slurry. The results of AAS and ICP-MS indicated that there were silicon oxide, Fe, Ni, Al and some other metal elements in the ultra-fine powders. XRD patterns showed the peaks of SiO2 at 2theta = 35.6 degrees, 39.4 degrees and 59.7 degrees and diamond sharp peaks in agreement with the results above. Diamond sharp peaks implied perfect crystal and high-hardness beneficial to high-efficiency in polishing. The broader Raman band of graphite at 1 592 cm(-1) observed by Raman analysis proved graphite existing in the diamond powders. In the TEM images, the size of ultra-fine powders was estimated between 0.1 and 0.5 microm distributed in a wide scope, however, sharp edges of the powder particles was useful to polish. The ultra-fine diamond powders have many advantages, for example, high-hardness, well abrasion performance, high-polishing efficiency and being useful in magnetic head polishing slurry. But, the impurities influence the polishing efficiency, shortening its service life and the wide distribution reduces the polishing precision. Consequently, before use the powders must be purified and classified. The purity demands is 99.9% and trace silicon oxide under 0.01% should be reached. The classification demands that the particle distribution should be in a narrower scope, with the mean size of 100 nm and the percentage of particles lager than 200 nm not over 2%.