Construction of cobalt sulfide/nickel core-branch arrays and their application as advanced electrodes for electrochemical energy storage

An approach of cobalt recovery from waste copper converter slags using pig iron as capturing agent and simultaneous recovery of copper and tin

Massive amounts of waste copper converter slags have been produced from pyrometallurgical extraction of copper from copper concentrates, and the disposal of them in landfills creates serious environmental problems. However, this converter slag contains numerous valuable heavy metals, including copper, cobalt and tin etc. In this research, due to similar properties of iron and cobalt, pig iron with a low melting point was creatively used as capturing agent for cobalt recycling in a smelting reduction. The recovery of copper and tin was also studied. The phase transformation during reduction process was clarified by X-ray diffraction and Scanning electron microscope-energy dispersive spectrometer analyses. After the reduction performed at 1250 °C, the copper, cobalt and tin were recovered in a copper-cobalt-tin-iron alloy. The addition of pig iron improved cobalt yield, which was ascribed to the enrichment of cobalt in an iron-cobalt alloy phase. This decreased activity of the reduced cobalt and promoted reduction of cobalt oxide. As a result, the cobalt yield had a significant increase from 66.2% to 90.1% by adding 2% pig iron. Similarly, the copper also accelerated tin recovery through the formation of a copper-tin alloy. The copper and tin yields reached 94.4% and 95.0%, respectively. This work provided a high efficiency method to recover copper, cobalt and tin from waste copper converter slags.

Electrodeposition Technologies for Li-Based Batteries: New Frontiers of Energy Storage

Electrodeposition induces material syntheses on conductive surfaces, distinguishing it from the widely used solid-state technologies in Li-based batteries. Electrodeposition drives uphill reactions by applying electric energy instead of heating. These features may enable electrodeposition to meet some needs for battery fabrication that conventional technologies can rarely achieve. The latest progress of electrodeposition technologies in Li-based batteries is summarized. Each component of Li-based batteries can be electrodeposited or synthesized with multiple methods. The advantages of electrodeposition are the main focus, and they are discussed in comparison with traditional technologies with the expectation to inspire innovations to build better Li-based batteries. Electrodeposition coats conformal films on surfaces and can control the film thickness, providing an effective approach to enhancing battery performance. Engineering interfaces by electrodeposition can stabilize the solid electrolyte interphase (SEI) and strengthen the adhesion of active materials to substrates, thereby prolonging the battery longevity. Lastly, a perspective of future studies on electrodepositing batteries is provided. The significant merits of electrodeposition should greatly advance the development of Li-based batteries.

Textile-based high-performance hydrogen evolution of low-temperature atomic layer deposition of cobalt sulfide

Hydrogen is an appealing green energy resource to meet increasing energy demands. To produce hydrogen using the hydrogen evolution reaction (HER), platinum, an expensive and scarce metal, is commonly used and plays a crucial role in maximizing catalytic performance. Transition metal chalcogenides, especially cobalt sulfides (CoSx), are considered an alternative to platinum because of their electrochemical properties, for example, low Tafel slopes and overpotentials. Here, we report a light weight, flexible textile-based HER catalyst through a low-temperature process using the atomic layer deposition (ALD) of CoSx. The electrochemical properties of HER catalysts were investigated and found to be impressive, with a low Tafel slope of 41 mV dec-1 and high exchange current density, demonstrating that these are one of the best characteristics among textile-based HER catalysts. The superb catalytic performances were attributed to the amorphous CoSx phase, confirmed by DFT calculations. This study demonstrates that the integration of HER catalysts with textiles allows the development of highly efficient hydrogen energy production systems.

A chemically modified graphene oxide wrapped porous hematite nano-architecture as a high rate lithium-ion battery anode material

Chemically modified graphene oxide wrapped porous hematite nanorods: an interconnected hollow network for excellent lithium storage in lithium ion batteries.