Tin-based anode material with good reversibility of conversion reaction for lithium ion battery

Abstract

Nanometerization of tin-based materials is beneficial to alleviate the volume effect, and thus improving the cycle stability of tin-based materials. Meanwhile, the smaller size can enhance the reversibility of the conversion reaction, which is crucial for increasing the capacity of tin-based materials. Therefore, reducing the size of tin-based materials may bring the advantages of cycle stability and specific capacity. In this work, we tried to disperse tin ions with organic skeleton to maximize the dispersion of active materials. Tin-based anode material based on polyethyleneimine‑sodium xanthogenate is synthesized by in-situ method at room temperature, and the thiocarboxyl group of polyethyleneimine‑sodium xanthogenate greatly increases the dispersion of metal ions. Carbon nanotubes (CNTs) are further introduced to improve the conductibility of tin-based materials owing to the existence of non-conductive organic groups. The anode material exhibits a long cycle life which delivers a specific capacity of 560 mAh g−1 after 1000 cycles. By analyzing the differential charge capacity (dQ/dV) curves, we find that the conversion reaction of tin-based materials is highly reversible.