A UiO-66-NH2 MOF derived N doped porous carbon and ZrO2 composite cathode for zinc-ion hybrid supercapacitors

Abstract

Aqueous Zn-ion hybrid supercapacitors (ZHSs) integrating the merits of Zn-ion batteries with high energy densities and supercapacitors with high power densities are considered one of the promising candidates for highly safe large-scale energy storage. Unfortunately, the unsatisfactory energy density of carbon-based cathode materials limited the practical application of ZHSs. A strategy of introducing heteroatoms and pseudocapacitive metal oxide materials into carbon materials is proposed to build ZHSs with better electrochemical performance. Herein, an N-doped carbon framework with homogeneously distributed nanoscale ZrO<inf>2</inf> (NC@ZrO<inf>2</inf>) was prepared by pyrolyzing Zr-containing metal-organic frameworks (MOFs, UiO-66-NH<inf>2</inf>). Due to the facilitated chemical adsorption and accelerated Zn²⁺-storage kinetics, the NC@ZrO<inf>2</inf>-based ZHS demonstrates a remarkable maximum energy density of 69 W h kg⁻¹ and a maximum power density of 5760 W kg⁻¹. This work provides a promising strategy to fabricate high-performance cathode materials for ZHSs by integrating the N-doping strategy and pseudocapacitive reactions, which sheds light on the charge-storage mechanism and advanced cathode material design for ZHSs toward practical applications.