Facile Synthesis of Ultrathin ZnO Nanotubes with Well-Organized Hexagonal Nanowalls and Sealed Layouts: Applications for Lithium Ion Battery Anodes

Abstract

We report a new facile route to synthesize the ZnO nanotubes by thermal annealing of solid nanorods in ambient NH3. The unique characteristic of this approach allows achievement of ultrathin nanotubes with well-organized hexagonal nanowalls and sealed layouts. On the basis of our experimental observations, we developed a nanotube formation mechanism illustrating the following: (i) energetically active nanorod surfaces could be readily passivated to form a few-atoms-thick Zn3N2 layer and (ii) nanopores generated from the seed layer were extended to the inside of nanorod bottoms and then propagated upward until they reached the tops of the nanorods. On the basis of key features of these tubular structures, we assessed the electrochemical performance of the nanotubes as anode materials in lithium ion batteries, demonstrating significant improvements in cycling performance over counterparts made of solid nanostructures.

Optimised synthesis of close packed ZnO cloth and its applications in Li-ion batteries and dye-sensitized solar cells

“…It is encouraging to see that the capacity keeps at about 600 mAh/g without significant fading from 10 cycles to 130 cycles, the excellent electrochemical performance can be attributed to the enhanced electron transport, shortened ion diffusion path, and the enhanced electro-active surface of the active materials. Furthermore, the ZnO cloth electrodes have high coulombic efficiency of nearly 100%, which is better than that previously reported [20,21,27].…”

“…The first discharge and charge capacity are 1450 and 1067 mAh/g respectively, which are both higher than the theoretical capacity for ZnO-based anodes (978 mAh/g). What's more, in the first discharge (delithiation) process, it exhibits a distinct and long plateau at 0.5 V, and is followed by a sloping curve down to the cutoff voltage of 0.01 V, which may be contributed to the formation of SEI and LiZn alloy reaction [20,21]. Moreover, we can see that the plateau only appears at the first cycle, because the reduction of ZnO to form Li 2 O and Zn is irreversible.…”

“…Among the available active materials, nanostructured metal oxides have always been regarded as very appealing candidates for LIBs and DSSC because of widespread availability, intrinsically enhanced safety and low processing cost [8,18]. Among which, higher theoretical capacity of 978 mAh/g than graphite (372 mAh/g) and similar bandgap (3.37 eV) with TiO 2 (theoretical capacity is 335 mAh/g), Zinc oxide (ZnO) has already attracted a great deal of interest of researchers to study its performance in LIBs and DSSC [19][20][21]. However, as an anode for LIBs, nanostructured ZnO electrode suffer from the low electronic conductivity and the loss of electrical contact arising from the volume expansion during the charge-discharge process which result in capacity degradation and poor cycling performance [22,23].…”

Reduced graphene oxide/carbon double-coated 3-D porous ZnO aggregates as high-performance Li-ion anode materials

“…[10][11][12][13][14][15][16][17][18][19][20][21]. Among these candidates, 3-D porous aggregates composed of nanoparticles clearly have two outstanding advantages: pores between nanoparticles act both as free spaces to accommodate the volume variations during cycling and as short diffusion paths of Li ions into the nanoparticles [22][23][24][25][26][27].…”

Ion beam induced evolution of surface morphology and optical properties of SnO2–ZnO nanocomposite thin films

“…nanorod [15], nanowire [16], nanotube [17], nanosheet [18] and nanodisk [19] has been reported for various applications. ZnO nanosheets are suggested to be ideal components of nanodevices used in energy conversion and storage, memory devices, gas sensing and optoelectronic devices due to their high surface-to-volume ratio and interesting optical, electronic and photocatalytic properties [20,21].…”