Ultrafine Au nanoparticles decorated NiCo2O4 nanotubes as anode material for high-performance supercapacitor and lithium-ion battery applications

Novel NiCo2O4@Au nanotubes (NTs) with a mesporous structure and hollow interiors have been synthesized by the electrospinning method followed by calcination in air. For supercapacitor application, the specific capacitance of NiCo2O4@Au NTs reached 1013.5 F g(-1) and could be maintained at 85.13% after 10,000 cycles at a current density of 10 A g(-1). The NiCo2O4@Au NTs were also used as the positive electrode to fabricate an asymmetric supercapacitor device with a maximum voltage of 1.45 V. The device exhibited high energy density (similar to 19.56 Wh kg(-1)), high power density (similar to 2115.01 W kg(-1) at 2.75 Wh kg(-1)) and outstanding cycling stability (79.05% retention after 4000 times). For LIBs application, the as-obtained NiCo2O4@Au nanotube electrodes showed a high reversible capacity of 732.5 mA h g(-1) even after 200th cycles at a current density of 100 mA g(-1) with good cycling stability. Au nanoparticles had not only penetrated into the whole electrode to form three dimensional percolation networks but also served as adhesion centers or mechanic anchoring points to tightly hold the adjacent NiCo2O4 particles together, which led to the superior tolerance ability of this electrode to volume expansion due to strain or stress from faster ion/electron transfer during cycling. (C) 2014 Elsevier Ltd. All rights reserved.