A New Free Standing ZnO/MWCNT Nanocomposite Anode Produced By Sol-Gel Spin Coating Method for Li-Ion Batteries

Lithium-ion batteries (LIBs) are one of the most popular types of rechargeable battery for portable electronics, with one of the best energy densities, and also the choice power source for electric and hybrid vehicles [1]. Zinc oxide is an attractive material as a potential substitute for the conventional graphite anode in lithium-ion batteries, because the theoretical capacity of ZnO (978 mAhg^-1) has been estimated to be superior to that of graphite (372 mAhg⁻¹) [2]. High capacity anodes such as zinc based usually suffer severe capacity fading, stemming from both the quick aggregation of zinc particles and the huge volume expansion during Li⁺ insertion/extraction cycles, which cause pulverization of the anodes and electrical detachment of active materials [3]. MWCNT buckypaper substrate is considered as a buffer material to prevent mechanical disintegration of anode material during the battery applications. In this work, ZnO/MWCNT buckypaper nanocomposite films were prepared as free-standing anode materials by sol–gel spin coating method. To the best of our knowledge there is no work to be published by using highly porous MWCNT buckypapers to be infiltrated with ZnO sol by spin coating. It was aimed to accommodate the stresses arisen from the volume increase during charging process by using highly porous MWCNT network that coated with a thin layer of the ZnO. The structural properties and electrochemical performance of free standing ZnO/MWCNT buckypaper composite film anodes of CR2016 type Li-ion batteries were investigated. SEM (Scanning Electron microscopy), EDS (Energy-dispersive X-ray spectroscopy), XRD (X-ray diffraction) analyses and electrochemical performance tests were performed to characterize the nanocomposites. The cells were charged and discharged at 25 °C between fixed voltage limits (2.5 V to 0.2 V) on an MTI model of BST8-MA battery tester.

[1] Y. Wang, F. Su, J.Y. Lee, X.S. Zhao, Chem. Mater., 18, 1347-1353 (2006).

[2] M.O. Guler, T. Cetinkaya, U. Tocoglu, H. Akbulut, Microelectronic Engineering, doi:10.1016/j.mee.2013.12.029 (2014).

[3] X.H. Huang, X.H. Xia, Y.F. Yuan, F. Zhou, Electrochim. Acta, 56, 4960-4965 (2011).