Porous carbon nanofibers as free-standing electrodes for zinc ion hybrid capacitor

Among the various carbon-based electrode materials, carbon nanofibers (CNFs) have emerged as a promising and indispensable candidate for zinc-ion hybrid capacitor (ZIHC) applications due to their unique structural and electrochemical properties. In this study, a facile and scalable strategy was developed to fabricate self-supporting, lightweight, and hierarchically macroporous activated carbon nanofiber electrodes (CZ-HPCNFs). Hollow CZ-HPCNFs nanostructures featuring enlarged specific surface areas and well-developed internal porosity were successfully fabricated through the dual strategy of employing calcium carbonate as a removable template and zinc chloride as a pore-forming agent, thereby achieving a synergistic integration of macroporous and microporous architectures. This hierarchical porous architecture facilitates rapid ion transport and provides abundant electrochemically active sites, thereby significantly enhancing both the specific capacity and rate performance of the resulting ZIHCs. As a result, the fabricated cell employing CZ-HPCNFs as the cathode delivers a notable specific capacity of 208 mAh g −1 at 0.1 A g −1 . Impressively, it maintains 95.6% of its initial capacity after 30,000 cycles. In addition, the template dispersion modulation strategy introduced in this study presents a flexible and broadly applicable framework for the engineered construction of porous electrode materials, offering significant potential for integration into next-generation energy storage technologies.