Metal–organic frameworks (MOFs) have attracted intensive attention for high-performance supercapacitors owing to their large specific surface area and tunable pore structure. Herein, ultrathin NiCo-MOF nanosheets are fabricated by a facile ultrasonication at room temperature and employed as a supercapacitor electrode material. The unique nanosheet-like structure of NiCo-MOF provides more electroactive sites and a shorter pathway for electron transfer and electrolyte diffusion, resulting in excellent electrochemical performance with a high specific capacitance of 1202.1 F g–1 at 1 A g–1. In addition, an asymmetric supercapacitor of NiCo-MOF//activated carbon was assembled in 2 M KOH electrolyte. It delivers an energy density of 49.4 W h kg–1 at a power density of 562.5 W h kg–1 in a voltage window of 1.5 V. The results demonstrate a new method to fabricate ultrathin MOF nanosheets for high-performance supercapacitor electrode materials.

Ultrathin NiCo-MOF Nanosheets for High-Performance Supercapacitor Electrodes

The activated carbon based electrode materials are promising for applications in supercapacitors, fuel cells, and batteries due to their large surface area and porous structure. All the carbonaceous materials (CNTs, graphene, activated carbon) exhibit EDLCs type behavior based on the adsorption of ions at the electrode interface. On the other hand, the charge storage mechanism of pseudo-capacitive materials, including metal oxides and conducting polymers, is based on the rapid faradic reactions. Owing to this, the latter has a higher level of charge storage than the former, but at the same time, it suffers from a lack of conductivity and lowers cycle stability. To achieve a higher energy density for the supercapacitor without degrading its power density and cycle stability, one of the best solutions is to compound the carbon based materials with pseudocapacitive materials. This review briefly described the various carbon composites with metal oxides, but the main focus is on biomass-derived activated carbon for supercapacitor applications, as the green and sustainable source of energy is the demand of ever increasing global crisis. The ongoing challenges and future developments in this direction for building efficient energy storage systems are also addressed here.

Biomass derived carbon for supercapacitor applications: Review

NiCo2S4-based nanocomposites for energy storage in supercapacitors and batteries

Enhanced electrochemical energy storage properties of carbon coated Co3O4 nanoparticles-reduced graphene oxide ternary nano-hybrids

Activated carbons are one of the possible electrode materials for supercapacitors (SCs), which are widely used in commercial applications. Herein, we reported the synthesis of a novel activated carbon derived through a cavitation process from the mixture of native European deciduous trees, Birch, Fagaceae, and Carpinus betulus (commonly known as European hornbeam), which was employed as the electrode material in SC. From the morphological and structural characterization, we observed that the prepared sample is a desirable carbon with good porosity and high specific surface area of about 614 m2 g−1. The electrochemical properties of the synthesized material were evaluated with a three-electrode configuration in 1.0 M H2SO4 electrolyte. It was found that in device mode, the carbon material delivers a specific capacitance of 24 F g−1 at 0.25 A g−1 with excellent cycling stability of over 10000 consecutive charge/discharge cycles. Thus, our studies demonstrate the facile synthesis of biomass-derived carbon and its application as a versatile electrode material for SC applications.

Biomass-derived activated carbon material from native European deciduous trees as an inexpensive and sustainable energy material for supercapacitor application

High performance quasi-solid-state supercapacitors with peanut-shell-derived porous carbon

Ionic liquid incorporated, redox-active blend polymer electrolyte for high energy density quasi-solid-state carbon supercapacitor

Pinecone-derived porous activated carbon for high performance all-solid-state electrical double layer capacitors fabricated with flexible gel polymer electrolytes

Optimization of porous polymer electrolyte for quasi-solid-state electrical double layer supercapacitor

Although nanostructured NiCo2O4 is the most appealing and studied electrode material by far as it is cheap, nontoxic, and efficient for supercapacitor application, it still lacks suitable device application comprising a wide voltage window and high operating current density, high specific energy and power, and absolute stability. Here, we report a successful application of our NiCo2O4 nanoparticles (NPs) in a highly efficient electrochemical supercapacitor device, which is brought to reality because of the NPs’ fast ion intercalation/extraction and fast reversible Faradaic surface reactions. The as-synthesized spinel NiCo2O4 NPs are 65 nm in average diameter, have 59 m2/g of surface area, and 0.44 cm3/g of pore volume. Charge storage capability and reliability of the material as an active electrode have been demonstrated in terms of a conventional three-electrode method and in a coin-cell device. Specific capacity values of 150.56 to 41.66 mAh·g–1 (1084 to 300 Fg–1 in terms of capacitance) have been reali...

Nitish Yadav

Papers

High performance quasi-solid-state supercapacitors with peanut-shell-derived porous carbon

Ionic liquid incorporated, redox-active blend polymer electrolyte for high energy density quasi-solid-state carbon supercapacitor

Pinecone-derived porous activated carbon for high performance all-solid-state electrical double layer capacitors fabricated with flexible gel polymer electrolytes

Optimization of porous polymer electrolyte for quasi-solid-state electrical double layer supercapacitor

Faster Ion Switching NiCo2O4 Nanoparticle Electrode-Based Supercapacitor Device with High Performances and Long Cycling Stability