A Layered Carbon Nanotube Architecture for High Power Lithium Ion Batteries

Abstract

Here we report the fabrication of a carbon-nanotube (CNT) based lithium ion electrode architecture, consisting of alternating layers of multi-walled carbon nanotubes (MWNT) and lithium ion active material, to significantly increase the aerial power and energy density of lithium ion battery cathodes. The CNT-based architecture aims to address engineering limitations of nanoscale active materials such as poor packing density, electrolyte reactivity, and costly fabrication. The alternating layers create a highly porous and highly conductive scaffolding to enhance ionic and electronic transport pathways within the electrode. The results show that the presented CNT-based architecture yielded excellent rate capability and highly stable cycling of lithium manganese oxide (LiMn2O4) active materials and lithium (Li) rich layered (xLi2MnO3·(1-x)LiMO2) materials. For LiMn2O4 materials, the CNT-based architecture demonstrates 14–20x higher aerial capacity over standard fabrication electrodes at discharge rates of 10C. For Li-rich layered materials, the CNT-based architecture demonstrates 70% higher aerial capacity over standard fabrication electrodes at discharge rates of C/2. Highly stable cycling for 100 cycles at 15C for LiMn2O4 and 500 cycles at 1C for Li-rich layered materials is also observed using the CNT-based architecture. The effect of the number of layers, layer thickness, and composition of the active material is investigated.