Tapping into the micro-sites in multiwalled carbon nanotube sheets: nanofibers versus trunk deagglomeration for...

We demonstrate an enhanced micro-site exposure capability to tap into the nanofibers as opposed to trunks consisting of Multiwalled Carbon Nanotube (MWCNT) bundles. We show this by accelerating the replenishment of the under exposed material within the active sonication zone during MWCNT sheet fabrication. Because high intensity acoustic cavitation (sonication) generates transient collapsing microscopic bubbles, control of deagglomeration quality becomes challenging. We herein demonstrate the ability of hydrodynamic optimization in providing improved deagglomeration, whilst reducing the MWCNT quality degradation (typically induced by sonication processes). The true value of this hydrodynamic investigation is revealed in the optimized electrochemical kinetics and enhanced apparent diffusion, which points to an optimized and un-collapsed porous network. Optimized electrodes achieved up to a 2.5-fold higher BET surface area (280.0 m² g^-1) and up to a 10.33-fold higher roughness factor (259.4). Consequently, charge transfer resistance dropped 5.9-fold for the negative (V³⁺/V²⁺) and 1.9-fold for the positive (VO²⁺/VO₂ ⁺) half-cell. Kinetic rate constants increased 2.0-fold for V³⁺/V²⁺ and up to 4.9-fold for VO²⁺/VO₂ ⁺, alongside a 3.9-fold rise in positive species diffusivity.