Hollow and Hierarchical Cobalt–Metal Organic Framework@CoCr₂O₄ Microplate Array as a Battery‐Type Electrode for High‐Performance Hybrid Supercapacitors

Abstract

Hollow metal-organic frameworks (MOFs) and their derived materials have shown fascinating structural complexity, such as diverse morphology, tunable porosity and hierarchical structure, which largely extends their intrinsic applications, especially in electrochemical energy storage and conversion. Herein, a hollow and hierarchical Co-MOF@CoCr 2 O 4 microplate array on nickel foam was successfully prepared through a simple onestep in situ conversion strategy, in which Co-MOF served both as self-supporting etching template and as a self-sacrificing ionexchange template. When used as a battery-type electrode for advanced hybrid supercapacitors, the Co-MOF@CoCr 2 O 4 composite expressed a high specific capacity of 596.8 C g À 1 at 0.4 A g À 1 , excellent rate properties (72.6 % retention rate at 10 A g À 1 compared with the initial capacitance at 0.4 A g À 1 ) and good cycling stability (85.1 % retention over 5000 cycles). Furthermore, a fabricated hybrid supercapacitor device reached a high energy density of 0.4 mWh cm À 2 (34.36 Wh kg À 1 ) at a power density of 2.34 mW cm À 2 (201.03 W kg À 1 ), and superior cycle stability (96.2 % retention over 5000 cycles). These enhanced electrochemical behaviors indicated that this advanced approach can be extended to design various hollow and hierarchical structural MOF/bimetallic-oxide-based composite arrays for high-performance hybrid supercapacitors.[a] Dr.

Synergistically Driven CoCr-LDH@VNiS2 as a Bifunctional Electrocatalyst for Overall Water Splitting and Flexible Supercapacitors

“…Moreover, the ASC device gives similar charging/discharging times under different bendings, which illustrates the excellent stability of the ASC device as depicted in Figure g. The energy density and power density are the most important parameters to evaluate the performance of the ASC device. , Figure h indicates the Ragone plots demonstrate the maximum energy density of 96.03 W h kg –1 at a power density of 539.98 W kg –1 , which is superior compared to the previously reported ASC devices such as CoO@CoAl-LDH, CoNi LDH/MnOX, NiCoP@NiFe-LDH, NiZn-LDH@NiCoSe 2 , Co-NiS/NCDs, and Co-MOF@CoCr 2 O 4 . The long-term cyclic stability of the CoCr-LDH@VNiS 2 ASC device is illustrated in Figure i.…”

Beyond Pristine Metal–Organic Frameworks: Preparation of Hollow MOFs and Their Composites for Catalysis, Sensing, and Adsorption Removal Applications

“…Among many candidate materials, hollow MOFs have great application potential. Han et al combined transition metal oxides with hollow MOFs as electrode materials for self-sustaining batteries, and the synthesized Co-MOF@CoCr 2 O 4 had a high specific capacity and excellent cyclic stability [79]. As for electrocatalysis, hollow-structure MOFs can effectively increase the reaction of active sites and improve the mass-transfer efficiency due to their abundant exposed active sites and large internal cavities, thus benefiting the electrocatalytic performance.…”

Metal–Organic Frameworks Constructed from Iron‐Series Elements for Supercapacitors

“…Other inorganic materials, such as TiO 2 , CoCr 2 O 4 , and Co(OH) 2 , were also chosen as counterparts to composite with MOF‐based active electrode materials, which also made remarkable achievements in enhancing the final performances. [ 177–179 ]…”

“…Other inorganic materials, such as TiO 2 , CoCr 2 O 4 , and Co(OH) 2 , were also chosen as counterparts to composite with MOF-based active electrode materials, which also made remarkable achievements in enhancing the final performances. [177][178][179] Notably, in a binary composite system, the composition of conducting matrix with conductive MOF system has also attracted broad interest in the SCs field. For example, the Han Group fabricated a CNFs@Ni-CAT composite by compositing the carbon nanofibers (CNFs) with 2D conductive Ni-CAT MOF (synthesized from 2,3,6,7,10,11-hexahydroxytriphenylene [HHTP] with Ni ions) through the combination of electrospinning technology with the hydrothermal method.…”