Waste catkins-derived graphitic carbon/Co3O4 composites as long-life and high-rate anodes for lithium-ion battery

Abstract

Upgrading waste re-utilization has been regarded as an important concept to promote the sustainable development of social economy. Herein, waste catkins were used as carbon source and template to prepare graphitic carbon/Co3O4 composites through cobalt salt immersion, in-situ carbonization and calcination. The obtained Co3O4/C composites inherit the microtubular structure of catkins with ultra-thin tube wall and large tube cavity. Particularly, the sample (Co3O4/C-280) calcined at 280 °C in air shows a morphology of the hollow Co3O4 spheres (av. 50 nm) evenly embedded on the biocarbon tube. As an anode for lithium-ion battery, such unique structure is more conductive to alleviate volume expansion. As expected, Co3O4/C-280 electrode has excellent rate capability at 5 A g−1 and stable long-cycle performance (647.3 mA h g−1, 1800 cycles, 1 A g−1). The presence of pseudo-capacitance behavior plays an important role in improving the capacity of material. The good electrochemical properties of Co3O4/C-280 can be ascribed to the synergistic effect of hollow tubular structure and graphitic carbon. Therefore, the strategy of making waste profitable is in line with the theme of green and sustainable development, and provides a reference for improving lithium storage performance of Co3O4-based anode materials.