Shortly Cut Carbon Nanotube as a Conductive Additive for High-Performance Silicon Anodes in Lithium-Ion Batteries

Abstract

Silicon (Si) anodes have garnered significant interest for next-generation energy storage systems due to their high theoretical capacity. However, Si anodes suffer from large volume expansion and poor electrical conductivity. Adding carbon nanotubes (CNTs) as a conductive additive is considered an effective method for addressing the aforementioned issues of Si. CNTs have a unique one-dimensional morphology and excellent conductivity, but strong van der Waals interactions and their long length cause severe aggregation and create entangled bulky structures that impede effective charge transfer within the electrode. Herein, we report shortly-cut CNT (SC-CNT) preparation using iron oxide nanoscrews via carbothermal reduction. The Si nanoparticle (SiNP) anode with an optimal length of the SC-CNT conductive agent showed improved rate and cycling performance with better capacity utilization. This could be attributed to the densely packed SC-CNT network, filling the interstitial space between nanoparticles while maintaining a wide-range conductive structure. The current study presents a promising strategy of CNT length control for the development of conductive additives in batteries.