First Intuition of Rate Capability Performance of Multiphase SiOC/C/NbC/Nb₂O₅ Anode Material for Battery Applications

Lithium-ion batteries (LiBs) are the most promising energy storage devices. Demand for the anodes should perform high charge capacity and good rate stability in a wide voltage window. Si-based composites derived from precursors (SiOC, SiOC/carbon, SiCN etc.) have been proven to be encouraging anode materials for LiBs with high charge capacity. Niobium pentoxide (Nb₂O₅) is recognized to be an efficient anode material with good rate stability. Hence for the first time, we fabricated the SiOC/Nb₂O₅ as a novel hybrid anode material for LiBs through the precursor derived ceramic route. X-ray diffractograms and electron microscopy were used to study phase evolution and microstructural characteristics. X-ray photoelectron spectroscopy the elemental composition, bonding nature, and presence of disordered and graphitic carbon of the SiOC/Nb₂O₅ composites were investigated using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. At a current density of 50 mAg-1, the electrochemical performance demonstrated by the first cycle discharge capacity of 685 mAhg^-1 and the first cycle charge capacity of 256 mAhg^-1, which is more than the theoretical capacity of Nb₂O₅ (200 mAhg^-1). After cycling at varied current densities, the capacity of these SiOC/Nb2O5 composites remained at 97% of their initial value at a current density of 50 mAg¹.