Ethylene glycol-mediated dispersion enhancement of oxidized MWCNTs for improved electrochemical performance in flexible, free-standing OCNT/LMO electrode

Abstract

The rapid advancement of flexible electronics and wearables necessitates high-capacity flexible batteries that adapt to various shapes and movements. Carbon nanotubes (CNTs), with their exceptional electrical conductivity, mechanical flexibility, and structural stability, are promising candidates. However, achieving a well-dispersed and uniform distribution of CNTs and heavy active materials like lithium manganese oxide (LMO) particles in different matrices is challenging due to issues with agglomeration and quick sedimentation. This study uses ethylene glycol (EG) as a dispersing solvent to form strong hydrogen bonds with oxidized CNTs, enhancing dispersion stability and preventing re-aggregation. Its higher viscosity compared to water helps in better stabilizing and dispersing LMO particles within the oxidized CNT suspension by reducing sedimentation. The OCNT/LMO-EG electrode shows a higher discharge capacity of 128 mAh/g with Coulombic efficiency of 99.6 % after 200 cycles, compared to the OCNT/LMO-W2 electrode, which uses water for dispersion and achieves 108 mAh/g with 99.6 % efficiency. These results highlight ethylene glycol's potential to improve CNT and LMO dispersion, resulting in a homogeneous electrode structure with enhanced conductivity and higher capacity. © 2024 Elsevier B.V.