Graphite–Si@TiO2 Core–Shell Nanoparticles as Composite Anode for Li‐Ion Batteries: Postcycling Analysis

Abstract

The present work deals with the postcycling analysis of the graphite‐based composite anodes, graphite reinforced with bare silicon nanoparticles (GrSi), and Si@TiO2 core–shell nanoparticles (GrCS), for lithium‐ion batteries. The electrochemical behavior is recorded through galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) tests. The postcyclic analysis is done using material and structural characterization. The GrSi anode demonstrates a higher initial specific capacity but lower cyclic stability relative to the GrCS anode. The capacity retention for the GrSi anode is ≈57%, while for the GrCS anode it is ≈75%. After cycling, the EIS analysis indicates that GrSi anode exhibits higher resistance than GrCS anodes. The cross‐sectional appearance of cycled anodes reveals minimal changes in the surface morphology of the GrCS anode, with a ≈75% thickness increase for the GrSi anode and ≈35% for the GrCS anode. The changed electrochemical behavior is attributed to the change in the composition of the solid–electrolyte interphase layer, as confirmed by X‐ray photo spectroscopy, and minor loss in crystallinity of GrCS anode material, as confirmed by X‐ray diffraction. The study provides insights into the mechanisms governing material degradation during the electrochemical processes in the composite anodes.