Graphite-Si@TiO₂ Core-Shell Nanoparticles as Composite Anode for Li-ion Batteries: Electrochemical Response

Abstract

This study focuses on optimizing composite anodes through varying Si@TiO2 core-shell nanoparticle percentages in graphite. Material characterization reveals the morphological transformation of graphite and silicon nanoparticles into composite anodes. Electrochemical tests, including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS), provide essential insights into the electrochemical behavior of these composites. In the cycling tests, Graphite with 5% core-shell (GrCS5), Graphite with 10% core-shell (GrCS10), and Graphite with 15% core-shell (GrCS15) show initial discharge capacities of 568, 675, and 716 mAh/g, retaining 76%, 75%, and 72% after 100 cycles, respectively. Conversely, the Gr/Si composite, commencing with 728 mAh/g, exhibits rapid degradation, retaining 54% after 100 cycles. Moreover, the EIS analysis reveals higher values of ohmic, solid electrolyte interphase, and charge transfer resistances in Graphite with 10% silicon (GrSi10) compared to other composite anodes after 100 cycles. The examination of the lithium diffusion coefficient indicates that GrCS5 demonstrates superior lithium diffusion kinetics, displaying the highest coefficient among all composite anodes. The research objective is to identify the optimal composite anode composition through quadrant analysis, considering specific capacity and lithium diffusivity after 100 cycles. In conclusion, integrating Si@TiO2 core-shell nanoparticles in graphite anodes improves their performance, with GrCS10 demonstrating notable effectiveness

Modeling Rate Dependent Volume Change in Porous Electrodes in Lithium-Ion Batteries

“…Lithium-ion batteries are used across the globe for a variety of applications, including grid storage, [1][2][3] off-grid power combined with solar 4 or wind 5 power, portable electronic devices such as laptops and cell phones, and electric vehicles. 6,7 As battery pack designs for electric vehicles increase in energy to meet range requirements and mitigate range anxiety 8 for consumers, higher energy density materials 9 such as silicon [10][11][12][13][14][15][16][17][18] containing materials have come into focus. Silicon and other high-capacity anode materials undergo significant volume change [19][20][21][22][23] during lithiation, [24][25][26] which can ultimately impact the performance of the battery pack and electric vehicle due to the engineering changes that must be made to account for the silicon volume change.…”