Ultrafine SnO2 coated by wheat straw-derived carbon used as anode for high-performance lithium ion batteries

Abstract

In this research, we separated cellulose from wheat straw by chemical treatment, and then coated it around the ultrafine nano-size SnO2 by a hydrothermal method to form a unique carbon coating. The elastic feature of carbon supports could provide a cushion effect against the volume strain and increase the electrical conductivity of the nanocomposite material. Additionally, two non-metal elements, nitrogen and sulfur have been added to the composite to form chemical bonds with the external amorphous carbon of composite material, which leading to a further improved electrochemical performance. The final synthesized composite material was named SnO2@WSC, when used as an anode for lithium-ion batteries, the specific discharge capacity of SnO2@WSC in the first cycle reached 1750 mA hg−1. And after 200 cycles, the discharge specific capacity reached 1130 mA hg−1 and 1100 mA hg−1 at 0.2C and 1C current respectively, which exhibits superior cycle stability.