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

SnO 2 nanoparticles encapsulated in polyaniline (PANI)-derived nitrogen-doped carbon composite powders (SnO 2 /NC) are successfully synthesized by in-situ polymerization and carbonization processes under an inert atmosphere . The results indicate that SnO 2 nanoparticles of the targeted powders (SnO 2 /NC-3) are uniformly dispersed in the N-doped carbon matrix when the added amount of SnCl 4 ·5H 2 O is precisely controlled at 3 mmol, in which PANI suppresses the aggregation of SnO 2 nanoparticles and is converted into N-doped carbon during the calcination process. The cell assembled with the SnO 2 /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 SnO 2 /NC-3 electrode also exhibits relatively high Li + ions diffusion coefficient of about 1.22 × 10 −12  cm 2  s −1 . The improved electrochemical performance can be partly ascribed to the fact that the proper amount of SnO 2 nanoparticles contributes to the enhancement of lithium storage capacity, and partly to that the N-doped carbon effectively relieves the volume expansion of SnO 2 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.