KOH-Activated\nHollow ZIF‑8 Derived Porous Carbon:\nNanoarchitectured Control for Upgraded Capacitive Deionization and\nSupercapacitor

Abstract

Herein, the synergistic effects of\nhollow nanoarchitecture and\nhigh specific surface area of hollow activated carbons (HACs) are\nreported with the superior supercapacitor (SC) and capacitive deionization\n(CDI) performance. The center of zeolite imidazolate framework-8 (ZIF-8)\nis selectively etched to create a hollow cavity as a macropore, and\nthe resulting hollow ZIF-8 (HZIF-8) is carbonized to obtain hollow\ncarbon (HC). The distribution of nanopores is, subsequently, optimized\nby KOH activation to create more nanopores and significantly increase\nspecific surface area. Indeed, as-prepared hollow activated carbons\n(HACs) show significant improvement not only in the maximum specific\ncapacitance and desalination capacity but also capacitance retention\nand mean desalination rates in SC and CDI, respectively. As a result,\nit is confirmed that well-designed nanoarchitecture and porosity are\nrequired to allow efficient diffusion and maximum electrosorption\nof electrolyte ions.