Silicon/Polyaniline Nanocomposites as Anode Material for Lithium Ion Batteries

Abstract

Due to of its high Li storage capacity, silicon is a promising anode material for lithium ion batteries. Unfortunately, this high specific capacity leads to extreme volume expansion of about 300% during lithiation and delithiation, that may lead to mechanical disintegration of the electrode and poor cycle life. To improve the cycling behavior, we combined nano-silicon (n-Si) active material with an inactive material that acts as a binder and buffering matrix. Stability, flexibility and conductivity are the main requirements for such matrix material. Polyaniline (PANi), a conducting polymer, meets all these requirements. With a theoretical capacity of 643 mAh g−1, the prepared n-Si/PANi sample showed a higher capacity in respect to the commonly used anode material, graphite. The electrochemical performance of the n-Si/PANi composite is stable compared to the performance of nano-silicon without PANi. After 300 cycles the composite still retains more than 60% of its theoretical capacity.