Versatile and Fast Electrochemical Activation Method for Carbon Nanotube Fibers with Diverse Active Materials

In this study, the challenge of non-electrochemical activity in carbon nanotube fibers (CNTFs) is addressed by developing a modified chlorosulfonic acid (CSA) densification process specifically developed for directly spun CNTFs. This post-treatment method, well-known for enhancing the physical properties of CNTFs, utilizes the double diffusion phenomenon to efficiently integrate a diverse range of active materials, from conductive polymers like polyaniline (PANI) to metal oxides like nickel oxide (NiO), into the fibers. This universal and cost-effective approach not only simplifies the integration process but also significantly boosts both the electrochemical and physical properties of the fibers. For instance, the PANI@CNTF composite exhibited a remarkable 17-fold increase in specific capacitance and a two-fold increase in load value compared to its pristine counterparts. This method proves straightforward, efficient, and versatile, making it suitable for developing fiber-shaped electrodes that advance the capabilities of wearable energy storage systems.