Sustainable Graphenothermal Reduction Chemistry to Obtain MnO Nanonetwork Supported Exfoliated Graphene Oxide Composite and its Electrochemical Characteristics

Abstract

Exfoliated graphene oxide (EG)/manganese(II) oxide (MnO) composite powder is synthesized by simple solid state graphenothermal reduction process. Structural, chemical, and morphological studies confirm the formation of EG/MnO composite in which cubic MnO crystallites are found to anchor onto EG surfaces. The as-synthesized EG/MnO composite is constituted with 65 and 35 wt % of MnO and EG, respectively. The EG/MnO composite exhibits a specific surface area of ∼82 m2 g-1 and an average pore size of ∼12 nm. As an anode in lithium-ion batteries, the EG/MnO composite shows a high reversible capacity of 936 mAh g-1 at a current rate of 75 mA g-1. Capacity retention of ∼84% (784 mAh g-1) is observed even at the 100th cycle which corresponds to a Coulombic efficiency of ∼99%. Cyclic voltammetry studies on the composite show that Li storage is owing to reversible conversion reactions of MnO and electrochemical absorption/desorption by EG. Electrochemical impedance spectroscopy studies clearly show easy lithiation kinetics. Owing to the electrochemical performance of EG/MnO composite and its easy, reproducible, and scalable synthesis procedure, it is an excellent addition to this class of similar materials.