Pouch-Type Asymmetric Supercapacitor Based on Nickel–Cobalt Metal–Organic Framework

Abstract

Bimetal–organic frameworks (BMOFs) have attracted considerable attention as electrode materials for energy storage devices because of the precise control of their porous structure, surface area, and pore volume. BMOFs can promote multiple redox reactions because of the enhanced charge transfer between different metal ions. Therefore, the electroactivity of the electrodes can be significantly improved. Herein, we report a NiCo-MOF (NCMF) with a three-dimensional hierarchical nanorod-like structure prepared using a facile solvo-hydrothermal method. The as-prepared NCMF was used as the positive electrode in a hybrid pouch-type asymmetric supercapacitor device (HPASD) with a gel electrolyte (KOH+PVA) and activated carbon as the negative electrode. Because of the matchable potential windows and specific capacitances of the two electrodes, the assembled HPASD exhibits a specific capacitance of 161 F·g−1 at 0.5 A·g−1, an energy density of 50.3 Wh·kg−1 at a power density of 375 W·kg−1, and a cycling stability of 87.6% after 6000 cycles. The reported unique synthesis strategy is promising for producing high-energy-density electrode materials for supercapacitors.

Solvent-Assisted Morphology-Induced Nickel Metal–Organic Framework as a Highly Efficient Electrode for Energy Storage Application

“…The slope line in the lower frequency region describes the ion diffusion path inside the electrode material. When electrolyte ions (OH – ) diffuse into the electrode material, they obtain resistance, which results in Warburg impedance . The smaller diameter of the semicircle of N-0.5//AC represents the lower ionic resistivity.…”

“…The pouch-type hybrid device was assembled (NCMF//AC), and its electrochemical performances were investigated via a PVA/KOH gel electrolyte. The assembled device exhibits an energy density of 50.3 W h kg –1 at a power density of 375 W kg –1 and a specific capacitance of 161 F g –1 at a current density of 0.5 A g –1 . Iqbal et al prepared Ni-MOF using a bilinker (Ni–P–H MOF) by solvothermal, and the fabricated hybrid device (Ni–P–H MOF//AC) shows a specific capacity of 268 C g –1 at 1.6 A g –1 .…”