Lithium-Ion Batteries Enhancing Cycling Performance of Silicon Graphite Anodes Using Carbon Nanotubes

Abstract

Silicon graphite anodes have emerged as promising candidates to replace conventional graphite anodes due to their higher theoretical capacity and ability to store more lithium ions. However, the significant volume expansion of silicon during lithiation and delithiation cycles results in severe mechanical degradation and rapid capacity fade, limiting their practical application. Additionally, the realisation of electrodes with high Si content are further limited by poor diffusion kinetics, resulting in an insufficient rate capability performance and lithium trapping.In this study carbon nanotubes (CNTs) are incorporated into the silicon graphite anode matrix as a strategy to mitigate these issues and enhance the cycling performance of LIBs. The CNTs, with their unique mechanical, electrical, and chemical properties, offer numerous benefits, including enhanced structural integrity, improved electrical conductivity, and increased lithium-ion diffusion kinetics. We investigated the effect of different ratios of CNTs on the cycling performance of silicon graphite anodes. The electrochemical performance of the composite electrodes were systematically evaluated using galvanostatic cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Preliminary results show that the addition of CNTs to silicon graphite anodes significantly improves their cycling stability and rate capability. The composites exhibit reduced capacity fade, improved coulombic efficiency, and enhanced rate performance compared to silicon graphite anodes absent of the CNTs, facilitated by faster lithium-ion diffusion kinetics, leading to improved electrochemical performance.