Co₃O₄@MWCNT Nanocable as Cathode with Superior Electrochemical Performance for Supercapacitors

Abstract

Using a simple hydrothermal procedure, cobalt oxide (Co3O4) with preferred orientation along (220) planes is in situ prepared and coated on MWCNT. The prepared Co3O4@MWCNT nanocable shows superior electrochemical performance as cathode material for aqueous supercapacitors in 0.5 M KOH solution. Its redox peaks retain the well-defined shapes even when the scan rate increases to 200 mV/s. Its specific capacitance is high, 590 F/g at 15 A/g and 510 F/g even at 100 A/g within the potential range from -0.2 to 0.58 V (vs SCE). There is no capacitance fading after 2000 full cycles. This excellent performance is superior to the pristine and the reported Co3O4, which is ascribed to the unique nanocable structure with orientation.

Ethanol-assisted solvothermal synthesis of porous nanostructured cobalt oxides (CoO/Co3O4) for high-performance supercapacitors

“…Up to now, various processing techniques have been adopted to tailor the structures of Co 3 O 4 and thereby enhance its electrochemical properties. For example, Wang et al reported fabrication of Co 3 O 4 @MWCNT nanocable using a simple hydrothermal procedure and it presented excellent rate capability for SCs [11]. Kumar et al prepared Co 3 O 4 nanofibers by electrospinning technique with a specific capacitance of 407 Fg À1 at a scan rate of 5 mV s À1 [12].…”

Co(OH)2 Nanosheets Coupled With CNT Arrays Grown on Ni Mesh for High-Rate Asymmetric Supercapacitors with Excellent Capacitive Behavior

“…Intensive researches have been carried out on cobalt/nickel-based materials, including Co(OH) 2 /graphene [19,20], Co 3 O 4 @MWCNT [21], NiO-Zn [22] …”

A Cr2O3/MWCNTs composite as a superior electrode material for supercapacitor

“…Transition metal oxides (TMO) such as MnO 16 and NiO 17 possess a higher pseudocapacitance and energy density compared with carbon materials. In general, use of metal oxides as supercapacitors is limited by their poor conductivity and lower specic surface area (SSA).…”