Polyaniline-Assisted
Synthesis of Si@C/RGO as Anode Material for Rechargeable Lithium-Ion
Batteries
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Abstract
A novel
approach to fabricate Si@carbon/reduced graphene oxides composite
(Si@C/RGO) assisted by polyaniline (PANI) is developed. Here, PANI
not only serves as “glue” to combine Si nanoparticles
with graphene oxides through electrostatic attraction but also can
be pyrolyzed as carbon layer coated on Si particles during subsequent
annealing treatment. The assembled composite delivers high reversible
capacity of 1121 mAh g<sup>–1</sup> at a current density of
0.9 A g<sup>–1</sup> over 230 cycles with improved initial
Coulombic efficiency of 81.1%, while the bare Si and Si@carbon only
retain specific capacity of 50 and 495 mAh g<sup>–1</sup> at
0.3 A g<sup>–1</sup> after 50 cycles, respectively. The enhanced
electrochemical performance of Si@C/RGO can be attributed to the dual
protection of carbon layer and graphene sheets, which are synergistically
capable of overcoming the drawbacks of inner Si particles such as
huge volume change and low conductivity and providing protective and
conductive matrix to buffer the volume variation, prevent the Si particles
from aggregating, enhance the conductivity, and stabilize the solid–electrolyte
interface membrane during cycling. Importantly, this method opens
a novel, universal graphene coating strategy, which can be extended
to other fascinating anode and cathode materials