One-pot Aerosol Synthesis of Carbon Nanotube-Zn2GeO4 Composite Microspheres for Enhanced Lithium-ion Storage Properties

Abstract

Three-dimensional (3D) carbon nanotube (CNT)-multicomponent metal oxide composite microspheres with non-aggregation characteristics are prepared using a simple one-pot spray pyrolysis process, applying water-soluble metal salt and oxidized CNT fibers. The hierarchical porous 3D structure of the CNT is formed by networking the flexible CNTs with a high aspect ratio during the drying stage of a droplet. Subsequently, the Zn and Ge salts are deposited over the CNTs to form the ZnO-CNT and GeO2-CNT composite microsphere. Decomposition of Zn and Ge salts into their respective oxides and the conversion reaction to form Zn2GeO4 at 700 degrees C, produce the Zn2GeO4-CNT composite microsphere. The initial discharge capacities of the Zn2GeO4, Zn2GeO4-CNT, ZnO-CNT, and GeO2-CNT microspheres, at a current density of 1.5 A g(-1), are 1351, 1211, 1387, and 1631 mA h g(-1), respectively, and their discharge capacities at the 300th cycle are 415, 762, 261, and 480 mA h g(-1), respectively. The CNT-Zn2GeO4 composite microspheres, selected as the first target material, show electrochemical properties superior to those of the bare Zn2GeO4, CNT-ZnO, and CNT-GeO2 composite microspheres. The synergetic effect of the multicomponent composition of Zn2GeO4 and the CNT support result in excellent Li-ion storage properties of the Zn2GeO4-CNT composite microspheres. (C) 2015 Elsevier Ltd. All rights reserved.