Ni–Co layered double hydroxide on carbon nanorods and graphene nanoribbons derived from MOFs for supercapacitors

Abstract

In this study, carbon nanorods (CNR) and graphene nanoribbons (GNR) derived from metal-organic frameworks (MOFs) were first prepared by solvothermal method. Then, Ni-Co layered double hydroxide (LDH)/CNR and LDH/GNR composite materials for supercapacitors were synthesized using a facile co-precipitation method. With the help of GNR, the Ni-Co LDH/GNR composite material showed great specific capacity (1765 F g-1), rate performance (68% capacity retention when current density increased from 1 to 20 A g-1) and cycling stability (83% capacity retention after 2000 charge-discharge cycles at 5 A g-1). Furthermore, an asymmetric supercapacitor (ASC) with Ni-Co LDH/GNR as positive and activated carbon (AC) as negative electrodes was fabricated. The ASC device delivered a high energy density of 25.4 W h kg-1 at power density of 749 W kg-1 and exhibited excellent cycling stability (96% specific capacity retention after 5000 cycles).

Hollow N‐ZIFs@NiCo‐LDH as highly efficient catalysts for 4‐nitrophenol and dyes

“…The peaks indexed as (003), (006), (009) and (110) are ascribed to a typical LDH structure. [26] The diffraction peaks of NiCo-LDH are consistent with the standard card (JCPDS no. 14-0191).…”

“…Recently, ZIFs have been used as templates for the synthesis of layered double hydroxides (LDHs) with unique hollow structure. [24][25][26] In addition, graphitic nitrogen plays an important role in the catalytic performance, which is attributed to the presence of graphitic nitrogen increasing the π-electron density in the carbon structure, thus improving the surface reactivity and electrical properties. [18] In the work reported here, three kinds of ZIFs with different forms were chosen as templates for the preparation of hollow mesoporous catalysts.…”

Review on Current Progress of MnO2‐Based Ternary Nanocomposites for Supercapacitor Applications

“…Again, layered double hydroxides (LDHs), as mentioned in the previous section, are basically inorganic sheets‐structured clay materials that are rapidly achieving popularity as promising electrode materials for energy storage applications [282] . LDHs entertain easy modifications of cations within the host layers as well as substitutions of anions in the interlayer corridors besides providing exceptionally large specific surface area with adjustable architectures [283] .…”

“…[281] Again, layered double hydroxides (LDHs), as mentioned in the previous section, are basically inorganic sheets-structured clay materials that are rapidly achieving popularity as promising electrode materials for energy storage applications. [282] LDHs entertain easy modifications of cations within the host layers as well as substitutions of anions in the interlayer corridors besides providing exceptionally large specific surface area with adjustable architectures. [283] Nonetheless, poor conductivity as well as fast aggregation during the processing leads to an exhibition of poor energy density in their pristine phases which can be satisfactorily addressed through suitable composites formation.…”

α- and β-Phase Ni-Mg Hydroxide for High Performance Hybrid Supercapacitors

“…However, α-Ni(OH) 2 tends to convert to β-Ni(OH) 2 in alkaline solution or when subjected to charge-discharge cycles [20]. Doping or partially substituting with other metal ions, such as Mg [21,22], Al [23][24][25][26], Mn [27], Fe [4], Co [28][29][30][31][32] or Zn [33] in α-Ni(OH) 2 has found to be an effective way to stabilize the crystal structure; the resulting complex nickel hydroxides have demonstrated much improved electrochemical properties and performance when used as electrodes in supercapacitors. For example, α-phase NiCoMn hydroxide demonstrated high power densities and high energy [34], CoAl hydroxide possessed enhanced electrochemical performance [35,36].…”