Hierarchical chestnut-like MnCo2O4 nanoneedles grown on nickel foam as binder-free electrode for high energy density asymmetric supercapacitors

Abstract

Hierarchical chestnut-like manganese cobalt oxide (MnCo2O4) nanoneedles (NNs) are successfully grown on nickel foam using a facile and cost-eff ective hydrothermal method. High resolution TEM image further verifies that the chestnut-like structure is assembled by numerous 1D nanoneedles, which are formed by numerous interconnected MnCo2O4 nanoparticles with grain diameter of ~10 nm. The MnCo2O4 electrode exhibits high specific capacitance of 1535 F g -1 at 1 A g -1 and good rate capability (950 F g -1 at 10 A g -1 ) in a 6 M KOH electrolyte. An asymmetric supercapacitor is fabricated using MnCo2O4 NNs on Ni foam (NF) as the positive electrode and graphene/NF as the negative electrode. The device shows an operation voltage of 1.5 V and delivers a high energy density of ∼60.4 Wh kg −1 at a power density of ∼375 W kg −1 . Moreover, the device exhibits an excellent cycling stability of 94.3% capacitance retention after 12000 cycles at 30 A g -1 . This work demonstrates that hierarchical chestnut-like MnCo2O4 NNs could be a promising electrode for the high performance energy storage devices.

AgCoO2−Co3O4/CMC Cloudy Architecture as High Performance Electrodes for Asymmetric Supercapacitors

“…They could achieve 1210 F g −1 at a current density of 2 A g −1 . A high energy density supercapacitor utilizing MnCo 2 O 4 electrodes (1535 F g −1 at 1 A g −1 ) was reported by Hui and his co‐workers …”

“…A high energy density supercapacitor utilizing MnCo 2 O 4 electrodes (1535 F g À 1 at 1 A g À 1 ) was reported by Hui and his co-workers. [17] Silver oxide is a fascinating metal oxide with various oxidation states (Ag + , Ag 2 + , Ag 3 + ) and high electrical conductivity (10 6 S cm À 1 ) . [18] The electrochemical performance of silver oxide (Ag 3…”

Mesoporous Nickel-Based Zeolite Capsule Complex with Fe3O4 as Electrode for Advanced Supercapacitor

“…In terms of the charge balance of asymmetric supercapacitors (ASCs), the principle q + = q − should be satisfied, where q + is the positive charges and q − is the negative charges. The voltammetric charges (q) were obtained by the following equation [17,18]:…”

Hierarchical MnCo2O4/NiMn Layered Double Hydroxide Composite Nanosheet Arrays on Nickel Foam for Enhanced Electrochemical Storage in Supercapacitors

“…Among these, MnCo 2 O 4 is a very attractive SCs electrode material because of its ultrahigh theoretical specific capacitance (3620 F g −1 ) and desirable physicochemical and electrochemical performance. To date, different MnCo 2 O 4 micro‐/nanostructures such as nanowires, nanofibers, nanoneedle, nanosheets, and flower‐like microspheres have been reported to demonstrate different capacitive performance . For instance, Yuan et al.…”