SnO2 nanoparticles uniformly encapsulated in polyaniline-derived nitrogen-doped carbon as anode materials for lithium-ion batteries

Abstract

SnO2 nanoparticles encapsulated in polyaniline (PANI)-derived nitrogen-doped carbon composite powders (SnO2/NC) are successfully synthesized by in-situ polymerization and carbonization processes under an inert atmosphere. The results indicate that SnO2 nanoparticles of the targeted powders (SnO2/NC-3) are uniformly dispersed in the N-doped carbon matrix when the added amount of SnCl4·5H2O is precisely controlled at 3 mmol, in which PANI suppresses the aggregation of SnO2 nanoparticles and is converted into N-doped carbon during the calcination process. The cell assembled with the SnO2/NC-3 electrode displays high initial discharge specific capacity of 1116.3 mAh g−1 and reversible discharge specific capacity of 567.2 mAh g−1 after 100 cycles at 100 mA g−1. Moreover, the SnO2/NC-3 electrode also exhibits relatively high Li+ ions diffusion coefficient of about 1.22 × 10−12 cm2 s−1. The improved electrochemical performance can be partly ascribed to the fact that the proper amount of SnO2 nanoparticles contributes to the enhancement of lithium storage capacity, and partly to that the N-doped carbon effectively relieves the volume expansion of SnO2 nanoparticles. Therefore, the proposed method of using PANI as N-doped carbon source may provide a feasible strategy to fabricate anode materials for high-performance lithium-ion batteries.