Rational Design of Bimetallic Oxide Multi-Nanoarchitectures for High-Rate and Durable Hybrid Supercapacitors

Designing porous multi-nanoarchitectures can be advantageous to reduce the ion impregnation and enhance the electrokinetics in the active materials of electrochemical energy storage devices. Herein, the nickel cobaltite (NiCo2O4) hybrid nanoarchitecture (NCO HNA) is prepared by using a facile wet-chemical method, followed by calcination. The effect of surfactants on the evolution of morphology is comprehensively investigated. The NCO HNA prepared with both the carbamide and methenamine as surfactants (NCO-C+M) demonstrates 1D nanorods along with 2D hexagonal nanosheets. Owing to its advantageous structural features, the NCO-C+M electrode exhibits maximum areal capacity of 154.7 mu Ah cm(-2) compared to the other electrodes, with decent capacity retention of 86.7% after 10 000 cycles. The hybrid supercapacitor (HSC) device is fabricated with NCO-C+M as a positive electrode and activated carbon as a negative electrode. The fabricated HSC device delivers a superior areal capacitance of 221.7 mF cm(-2) at 1.5 mA cm(-2) and still retains 93.2% at a high current density. Besides, the HSC displays a high energy density of 67.8 mu Wh cm(-2) and a high power density of 19545 mu W cm(-2), with good cycling efficiency (81.3%) after 10 000 cycles. The practicability of HSC is further tested by powering-up various electronic components.

Automated summary

Porous multi-nanoarchitectures have been designed and prepared for electrochemical energy storage devices, such as hybrid supercapacitors, showing advantages in both capacity and stability. One of the developed NiCo2O4 nanoarchitectures, NCO-C+M, exhibits superior performance as a positive electrode, delivering high energy and power density as well as good cycling efficiency.