Ultrathin Mn Doped Ni‐MOF Nanosheet Array for Highly Capacitive and Stable Asymmetric Supercapacitor

Abstract

In this study, we demonstrate that an Mn‐doped ultrathin Ni‐MOF nanosheet array on nickel foam (Mn0.1‐Ni‐MOF/NF) serves as a highly capacitive and stable supercapacitor positive electrode. The Mn0.1‐Ni‐MOF/NF shows an areal capacity of 6.48 C cm−2 (specific capacity C: 1178 C g−1) at 2 mA cm−2 in 6.0 m KOH, outperforming most reported MOF‐based materials. More importantly, it possesses excellent cycle stability to maintain 80.6 % capacity after 5000 cycles. An asymmetric supercapacitor device utilizing Mn0.1‐Ni‐MOF/NF as the positive electrode and activated carbon as the negative electrode attains a high energy density of 39.6 Wh kg−1 at 143.8 Wkg−1 power density with a capacitance retention of 83.6 % after 5000 cycles.

High-performance quasi-solid-state flexible supercapacitors based on a flower-like NiCo metal–organic framework

“…This could be explained interpreted that Co 2+ partially replaced Ni 2+ in the metal–organic framework, retaining the crystal structure of C 8 H 6 NiO 5 ·H 2 O. 25,29,30 …”

“…2(e), the O 1s spectrum was deconvoluted into two peaks at 530.8 and 533 eV, which were associated with the C-O and metal-oxygen bonds M-O-M, respectively. 25,33 The C 1s spectrum (Fig. 2(f)) showed two peaks at 288.6 and 284.8 eV, which were associated with the O-C]O, C-C bonds of terephthalate, respectively.…”

“…As shown in Fig.2(d), the satellite peaks of Co 2p 3/2 and Co 2p 1/2 were located at 788.1 eV and 804.6 eV, respectively, and the main peaks of Co 2p 3/2 and Co 2p 1/2 were 783.5 eV and 799.3 eV, with a spin-energy separation of 15.8 eV, indicating that the Co element in NiCo MOF-2 existed in the form of Co 2+ 33,39. As shown in Fig.2(e), the O 1s spectrum was deconvoluted into two peaks at 530.8 and 533 eV, which were associated with the C-O and metal-oxygen bonds M-O-M, respectively 25,33. The C 1s spectrum (Fig.2(f)) showed two peaks at 288.6 and 284.8 eV, which were associated with the O-C]O, C-C bonds of terephthalate, respectively 31,37.…”

“…22 However, the most of MOFs with inherent low conductivity limit the application in supercapacitors. [23][24][25] In order to improve conductivity of MOFs, the preparation of different structures and combinations of MOFs becomes one of the current research directions. [26][27][28] Many studies have showed that MOFs with a unique structure exhibit a large specic surface area, reducing the diffusion distance of electrolyte ions, thus achieving an increase in conductivity.…”

An overview of supercapacitors electrode materials based on metal organic frameworks and future perspectives

“…In addition, a practical device employing Mn 0.1 -Ni-MOF/NF (positive electrode) and activated carbon (negative electrode) as electrodes attain a huge energy density and power density of 39.6 Wh/kg and 143.8 W/kg, respectively. 173 In the case of Ni-based compound it has been observed that electrochemical response of Ni based MOF is superior to Co-Based MOF due to better conductivity and transformation of Ni-MOF into Ni (OH) 2 work as a catalyst for electrochemical activity. As compared to single metal MOF, the incorporation of second metal results in improved conductivity of MOF without calcination process.…”