Metal–Organic Framework Derived Honeycomb Co₉S₈@C Composites for High‐Performance Supercapacitors

Abstract

Unique nanostructures always lead to extraordinary electrochemical energy storage performance. Here, the authors report a new strategy for using Metal‐organic frameworks (MOFs) derived cobalt sulfide in a carbon matrix with a 3D honeycombed porous structure, resulting in a high‐performance supercapacitor with unrivalled capacity of ≈1887 F g‐1 at the current density of 1 A g‐1. The honeycomb‐like structure of Co9S8@C composite is loosely adsorbed, with plentiful surface area and high conductivity, leading to improved Faradaic processes across the interface and enhanced redox reactions at active Co9S8 sites. Therefore, the heterostructure‐fabricated hybrid supercapacitor, using activated carbon as the counter electrode, demonstrates a high energy density of 58 Wh kg‐1 at the power density of 1000 W kg‐1. Even under an ultrahigh power density of 17 200 W kg‐1, its energy density maintains ≈38 Wh kg‐1. The hybrid supercapacitor also exhibits suitable cycling stability, with ≈90% capacity retention after 10 000 continuous cycles at the current density of 5 A g‐1. This work presents a practical method for using MOFs as sacrificial templates to synthesize metal‐sulfides for highly efficient electrochemical energy storage.

In Situ Formation of Co9S8 Quantum Dots in MOF‐Derived Ternary Metal Layered Double Hydroxide Nanoarrays for High‐Performance Hybrid Supercapacitors

“…Apparently, in situ formation of cobalt sulfide within LDHs is a practical and effective method to derive more stable and excellent electrode materials because of the unique advantages of cobalt sulfide, such as weak CoS bonds, low solubility product, easy conversion reaction, large theoretical capacity, and high intrinsic conductivity . However, large volume change and sluggish ion diffusion are still the major constraints to expanding the high electrochemical performance .…”

A Core‐Shell Assembly of Hierarchical Porous Ni@C Nanospheres Synthesized from Metal‐Organic Framework for Electrochemical Energy Application

“…Among such devices, the supercapacitor has attracted a lot of attention for electrochemical energy storage lately because of its remarkable performance and efficiency including user‐friendly operation, short charging time, long‐term cycling stability, and high power density . The supercapacitor includes two types: an electrical double layer capacitor (EDLC) and pseudocapacitor (PC) . Compared to EDLCs, the pseudocapacitor maintains high specific capacity and power density, attributed to the rapid redox reversibility .…”

Redox Tuning in Crystalline and Electronic Structure of Bimetal–Organic Frameworks Derived Cobalt/Nickel Boride/Sulfide for Boosted Faradaic Capacitance

“…Recently, metal–organic frameworks (MOFs), which are self‐assembled by metal ions (or metal clusters) with organic ligands in high crystallinity and long‐range order, are considered as emerging porous materials for electrochemical energy storage applications . In sharp contrast to the inorganic electrode materials, their diverse topology structure, tunable porosity, and abundant metal ions allow them to be a promising energy storage material .…”