Nitrogen-doped graphene/silicon-oxycarbide nanosphere as composite anode for high-performance lithium-ion batteries

Abstract

The N-Graphene/SiOC nanosphere composite was prepared using the thermal polymerization method. Investigations were focused on the structural, morphological, chemical composition, and lithium-ion storage capabilities of N-Graphene/SiOC. The amorphous nature and nanosphere morphology of N-Graphene/SiOC was established by XRD and TEM results. The existence of a distorted carbon phase in both SiOC and N-Graphene/SiOC was revealed by Raman spectrum investigations. The presence of nitrogen elements in the composite has released additional electrons and attracted lithium-ions during the charge/discharge process. The nanosphere composites have good reversibility and capacity retention, which was represented by the cyclic voltammetry study. The nanosphere composite has delivered the initial discharge capacity of 1324 mAhg−1 at a current density of 100 mAg−1, which was higher than 850 mAhg−1 for SiOC and 219.8 mAhg−1 for g-C3N4 anode materials in lithium-ion battery applications. After 1000 cycles at a current density of 1000 mAg−1, the specific capacity retention was 415.8 mAhg−1 for N-Graphene/SiOC. It shows the coulombic efficiency at around 99 %, with 67 % capacity retention in the 1000th cycle. Moreover, nanosphere N-Graphene/SiOC exhibited excellent electrochemical activity, demonstrating high lithium-ion storage capability as an anode material for high-performance lithium-ion batteries.