Optimization of Carbon Nanotubes as Conductive Additives for High-Energy-Density Electrodes for Lithium-Ion Batteries

Development of a high-energy-density electrode to use in lithium-ion batteries (LIBs) is imperative for automotive applications. Although extensive efforts are put on developing high-capacity cathode and anode materials for high-energy-density electrodes, challenging issues involving both the cathode and anode hinder practical application of the materials developed to date. Therefore, a practical approach to increase the energy density of LIBs is to design an electrode that has higher active material loading and a low fraction of nonactive materials. The present study demonstrates the use of carbon nanotubes (CNTs) as conductive additives for a high-energy-density electrode and reports the effect of the content of CNTs and binder on the slurry, electrode, and electrochemical performance of a cell. The electrochemical results and thermomechanical analysis reveal that the conductive network formed by CNTs and the binder plays a role in maintaining electrode integrity, thereby influencing cycle retention. Moreover, an electrode resistance analysis combined with electrochemical results shows that the ratio of CNTs and binder is a crucial factor in determining the rate capability. This understanding of the conductive network of CNTs/binder offers an insight into strategies to design high-energy-density LIBs.