In situ coating of NiO on Ni-silicide nanowires with roughened surfaces for improved electrochemical energy storage

Abstract

NiO layers were coated in situ onto Ni-silicide nanowires by an oxidation in air. The surface of the nanowires had been previously roughened by etching in HF solution. It is found that the roughened surface is very helpful to enhance the in situ coating ability of NiO on the nanowires. When the resulting samples were used as anodes for lithium-ion batteries, a high reversible capacity of 1.28 mA h cm À2 was obtained for the surface-roughened nanowires with 30 min HF-treatment, which is 3 times higher than that of the nanowires without HF-treatment. The current density can reach up to 2.15 mA cm À2 for the 60 min HF-treated and then oxidized nanowires, while the capacity is maintained at as high as 0.52 mA h cm À2 . The improved cyclic performance could be attributed to the roughened surface of the nanowires, which enhanced the coating ability of the NiO layers, and provided a porous structure that is of benefit to increase the area of the electrode/electrolyte interface for the adsorption of ions. In addition, the Ni-silicide nanowires can improve the electrode conductivity and act as a stable support for the NiO coating layers during cycling, making a positive contribution to the electrochemical performance.

Silver–nickel oxide core–shell nanoflower arrays as high-performance anode for lithium-ion batteries

“…More recently, core-shell nanostructures with conductive matrices have been realized to be an effective approach to address the above-mentioned issues, in which the core functions as a built-in current collector to accommodate the enormous volume change and facilitate the electron collection and transport [29][30][31][32][33][34]. For instance, Huang et al reported Ni micro-nanocone hierarchical electrodes by economical electrodeposition method with a crystallization modifying agent, which showed outstanding Li storage properties with reversible capacity over 800 mAh g -1 after 100 th cycle [35].…”

Controlling electric potential to inhibit solid-electrolyte interphase formation on nanowire anodes for ultrafast lithium-ion batteries

“…NiSiNWs are explored as an active anode material; these NWs are attractive due to their potential for high-capacity and good rate capability, as well as their low-temperature growth in the presence of Ni and Si precursors (~450 °C) 20 . NiSi has a gravimetric capacity of ~1300 mAh g −1 , 21 – 23 which is lower than that of Si but still much higher than graphite. An additional advantage of NiSi is related to its metallic conduction, with a typical resistivity of ~10 μΩ cm for single crystals 24 .…”