Carbon coated porous Co3O4 polyhedrons as anode materials for highly reversible lithium-ion storage

Abstract

Co3O4 is considered a promising anode candidate for lithium ion batteries (LIBs) owing to its high theoretical capacitance. However, the electrochemical properties of bare Co3O4 for LIBs remain seriously limited by poor electronic conductivity and large volume expansion. Herein, carbon-coated porous Co3O4 polyhedrons with (220) facets are fabricated through a hydrothermal method and subsequent calcination process. The size of Co3O4 polyhedrons ranges from 70 nm to 170 nm. The continuous amorphous carbon layer is approximately 3 nm thick, and uniformly covers the surface of Co3O4. Moreover, the discharge capacity of carbon-coated porous Co3O4 anode reaches 1463 and 596 mA h g−1 at 100 and 5000 mA g−1, respectively. After 150 charge discharge cycles, the carbon-coated Co3O4 anode still exhibits a reversible capacity of 840 mA h g−1 at 1000 mA g−1. Carbon nano-coating, mixed conductive matrix, and crystalline texture design can enhance the electrochemical performance of Co3O4.