Effect of aluminium doping amount on the electrochemical properties of ZnO nanoparticles as anode for lithium ion batteries

Abstract

Aluminium (Al)-doped ZnO nanoparticles (NPs) have been synthesised by a simple solvothermal method at low temperature. The electrochemical properties of the obtained products as anode for lithium ion batteries were examined through galvanostatic dischargecharge, cyclic voltammetry and electrochemical impedance spectroscopy measurements. The results show that the reversible capacities of Al-doped ZnO NPs are higher than the capacities of pure ZnO synthesised under the same experimental conditions. ZnO NPs doped with 2% (molar ratio) of Al show the best electrochemical properties with reversible specific capacities of 418 mA·h·g −1 at a current density of 50 mA·g −1 . The enhanced electrochemical performance of this material could be attributed to the improved electronic conductivity because of the doping of Al 3+ at an appropriate concentration.1. Introduction: Rechargeable lithium ion batteries (LIBs) have been widely utilised as power sources for portable electric devices and electric vehicles because of their relatively high energy density [1][2][3]. In principle, the electrochemical performances of LIBs depend strongly on the materials used for the anode, cathode and the electrolyte. As conventional anode materials, graphite and related materials exhibit stable electrochemical properties, but the relatively low specific capacity (∼372 mA·h·g −1 ) and poor rate capability limit their applications in high power LIBs [4]. Thus, the exploitation of new LIB anode materials with enhanced electrochemical performances has attracted extensive attention.Metal oxides show great potential as the anode in LIBs with high specific capacities [5][6][7]. Among these materials, ZnO is one of the most promising candidates because of its compatible theoretical capacity [8], low cost and environmental benignity [9]. However, so far, ZnO has rarely been used in LIBs because of its low electronic conductivity and large volume change during the process of insertion/extraction of lithium ions [10,11]. To overcome these problems, the effects of the morphology and size of ZnO particles on their electrical properties have been systematically studied [12,13]. Alternatively, it was found that the electrical and electrochemical behaviours of ZnO can be improved via doping hetero-elements [14]. It has been demonstrated that the electrical conductivity of ZnO can be significantly improved through doping the heteroelements such as aluminium, gallium and indium [15][16][17]. On the basis of these results, we reasoned that Al-doped ZnO nanoparticles (NPs) should be a suitable candidate for anode materials in LIBs.In the work reported in this Letter, Al-doped ZnO NPs were synthesised using a simple solvothermal method at low temperature. The composition and morphology of the as-synthesised Al-doped ZnO NPs were systematically characterised. The electrochemical properties of Al-doped ZnO NPs as the anode for LIBs have been elaborated and it was found that the ion capacity of Al-doped ZnO NPs is much higher than that of pure ZnO NPs.

Temperature effect on morphology and electrochemical properties of nanostructured ZnO as anode for lithium ion batteries

“…4 c shows the CV curves of the ZnO nanoparticles acquired at 700°C at scanning rate of 0.1 mV s −1 . During the first scan, there is one strong reduction peak at 0.26 V, which is related to the reduction of ZnO, the formation of lithium‐zinc alloy and the growth of SEI layer [5, 12, 25]. In the corresponding anodic scan, four oxidation peaks appeared at 0.28, 0.35, 0.52 and 0.67 V, which correspond to the multi‐step dealloying process of lithium‐zinc alloy.…”

“…Introduction: Zinc oxide (ZnO) has been attracted much attention as a promising anode material for lithium ion batteries (LIBs) due to its low-cost, environmental benignity and high theoretical capacity of 987.7 mAh g −1 [1], while its drawbacks including low electrical conductivity and strong volume variation constantly affect their applications in LIBs [2,3]. To overcome the problems, the electrochemical properties of ZnO could be improved by incorporating carbon materials [4] or doping with hetero-elements [5,6]. In addition, another important strategy is fabricating nanostructured ZnO with especial morphology, such as nanorods [7,8], nanosheets [9], nanospheres [10], nanotubes [11] as well as mesoporous ZnO [12], which could effectively improve the lithium intercalating activity and cycling stability of the electrode materials.…”

Electrical properties of Aluminium doped Zinc Oxide nanorods with different dopant percentage

“…al, [24] also discussed that increased the doping leads to decreased the conductivity which is probably due to the deformation of ZnO lattices and the limitation of electron transport.…”

Mg-Composition Dependent Cycle Stability in Zn_1-xMg_xO Li-ion Battery: Transition from Electronic Transport-Limited to Ionic Transport Limited Cycles

“…Zhang et al reported that Aluminum (Al)-doped zinc oxide (ZnO) nanoparticles, particularly those with a 2% molar ratio of Al, exhibited superior reversible capacities compared to undoped ZnO under the same experimental conditions [11].…”