Carbon nanomaterials-Based Inks and Electrodes Using Chitin Nanocrystals

Dispersing 1D carbon nanomaterials (CNMs) for film processing traditionally relies on surfactants or organic solvents. These methods, however, raise environmental concerns and can negatively impact the final properties of the CNMs. In this work we demonstrate that chitin nanocrystals (ChNCs) synthesized via acid hydrolysis provide a greener pathway for the development of waterborne CNMs-based inks, including single-walled carbon nanotubes, multiwalled carbon nanotubes, and carbon nanofibers. Various concentrations of ChNCs were mixed with each type of CNM to maximize the CNM concentration within the ink. In-depth characterization of the CNM/ChNC inks preceded their processing into supported conductive films by spray-coating. A subsequent thermal treatment of ChNCs at 450 °C leads to the efficient removal of ChNC and results in a significant enhancement of the electrical conductivity. Moreover, freeing the CNMs network structure contributes to increased electrochemical performance of the treated films, as expressed by improved Faradaic charge transfer efficiencies and kinetics reflected by 1 order of magnitude reduced rate constants, when tested with various redox probes. Our findings highlight the potential of ChNCs as a sustainable processing adjuvant of CNMs, leading to electrically conductive electrodes with suitable electrochemical properties for their use in diverse devices and applications.