Hybrid nanostructure of sanwhich-like porous Co3O4 nanorods/exfoliate graphite composite for lithium-ion batteries

Abstract

High rate capacity and long cycling life are the main properties that expand the application of Co3O4 as anode materials, which are largely dependent on their structure and conductivity. In this work, we provide a facial method to achieve sanwhich-like exfoliate graphite-Co3O4 porous nanorods (EG/Co3O4) by two-step method hydrothermal and carbonization using EG as the conductivity matrix. The SEM and TEM analyses showed that EG successfully embed into the inner part of the Co3O4 nanorods. The addition of EG not only enhances the conductivity of the Co-based materials but also alleviates the aggregation of nanoparticles, while providing a large contact area for the electrode-electrolyte interface. This leads to an excellent rate capacity of 508 mAh g−1 at 5 A g−1. Moreover, the Co3O4 nanorods consist of interconnected nanoparticles, which help reduce the distance that lithium ions need to diffuse and facilitate electron transport. This capability effectively addresses the severe volumetric variation and contributes to optimal cycling performance, resulting in a high charge capacity of 847 mAh g−1 over 200 cycles at 0.5 A g−1. The outstanding electrochemical performance of EG/Co3O4 makes it a highly favorable option for use in lithium-ion batteries.