Uniform Decoration of Vanadium Oxide Nanocrystals on Reduced Graphene‐Oxide Balls by an Aerosol Process for Lithium‐Ion Battery Cathode Material

Abstract

VO2-decorated reduced graphene balls were prepared by a one-pot spray-pyrolysis process from a colloidal spray solution of well-dispersed graphene oxide and ammonium vanadate. The graphene-VO2 composite powders prepared directly by spray pyrolysis had poor electrochemical properties. Therefore, the graphene-VO2 composite powders were transformed into a reduced graphene ball (RGB)-V2O5 (RGB) composite by post-treatment at 300 °C in an air atmosphere. The TEM and dot-mapping images showed a uniform distribution of V and C components, originating from V2O5 and graphene, consisting the composite. The graphene content of the RGB-V2O5 composite, measured by thermogravimetric analysis, was approximately 5 wt %. The initial discharge and charge capacities of RGB-V2O5 composite were 282 and 280 mA h g(-1), respectively, and the corresponding Coulombic efficiency was approximately 100 %. On the other hand, the initial discharge and charge capacities of macroporous V2O5 powders were 205 and 221 mA h g(-1), respectively, and the corresponding Coulombic efficiency was approximately 93 %. The RGB-V2O5 composite showed a better rate performance than the macroporous V2O5 powders.

Large-Scale Production of MoO 3 -Reduced Graphene Oxide Powders with Superior Lithium Storage Properties by Spray-Drying Process

“…Therefore, graphene-metal oxide composite materials with various compositions have been developed by various synthetic processes. Graphene-based composites prepared by liquid solution and spray pyrolysis processes have shown superior electrochemical properties as compared to bare metal oxides [29][30][31][32][33][34][35]. However, effective large-scale production of graphene-metal oxide composite materials having micronsize spherical particles for possible application in commercial LIBs has to be developed.…”

A Direct Hybridization between Isocharged Nanosheets of Layered Metal Oxide and Graphene through a Surface‐Modification Assembly Process

“…[19][20][21][22][23] The enhancement of electrical conductivity and the formation of porous stacking structures upon the hybridization with rGO nanosheets lead to the improvement of their electrode performance at high current density and the accommodation of large volume change during electrochemical cycling. [24][25][26] However, it is not easy to directly hybridize the negatively charged nanosheets of layered metal oxides with isocharged rGO nanosheets due to electrostatic interactions. To overcome this difficulty, it is desirable to modify the negative charge of rGO nanosheets to a positive charge.…”

Superior electrochemical properties of spherical-like Co2(OH)3Cl-reduced graphene oxide composite powders with ultrafine nanocrystals

“…Recently, the preparation of metal oxide/reduced graphene oxide (RGO) and metal sulfide/RGO composite powders by one-pot spray pyrolysis was reported [46,47]. In this study, for the first time, we demonstrate that metal hydroxychloride/RGO composites prepared by one-pot spray pyrolysis are promising LIB anode materials.…”