AUTHOR=He Da , Gao Yu , Yao Yucen , Wu Ling , Zhang Jiang , Huang Zheng-Hong , Wang Ming-Xi 

TITLE=Asymmetric Supercapacitors Based on Hierarchically Nanoporous Carbon and ZnCo2O4 From a Single Biometallic Metal-Organic Frameworks (Zn/Co-MOF)

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00719

DOI=10.3389/fchem.2020.00719

ISSN=2296-2646

ABSTRACT=Metal-organic frameworks (MOFs) have triggered numerous interests in supercapacitos (SCs) due to
their large specific surface area and tunable pore structure, but their poor electrochemical conductivity and
ion insertion steric hindrance limit their use as high-performance electrodes of supercapacitors. Bimetallic
MOFs could provide rich redox reactions deriving from improved charge transfer between different metal
ions, so their supercapacitor performance can be enhanced greatly. In this study, “One-for-All” strategy is
adopted to synthesize both positive and negative electrodes for hybrid asymmetric SCs (ASCs) from a
single bimetallic MOF. Bimetallic Zn/Co-MOF with cuboid-like structures were synthesized by a simple
method, the MOF-derived nanoporous carbons (NPC) and bimetallic oxides (ZnCo 2 O 4 ) were obtained by
post heat treatment and rinsing with HCl. The as-prepared MOF derived NPC and bimetallic oxides were
utilized as negative and positive materials to assemble hybrid ASCs with 6 M KOH as electrolyte. Thanks
to the matchable voltage window and specific capacitance between the negative (NPC) and positive
(ZnCo 2 O 4 ), the as-assembled ASCs deliver high specific capacitance of 94.4 F/g (cell), excellent energy
density of 28.6 Wh/kg at a power density of 100 W/kg, and high cycling stability of 87.2% after 5000
charge-discharge cycles. This strategy is promising in producing high-energy-density electrode materilas in
supercapacitors.