High performance alkaline battery-supercapacitor hybrid device based on diffusion driven double shelled CoSn(OH)6 nanocube@∝-Ni(OH)2 core-shell nanoflower

Abstract

The design and fabrication of an alkaline battery-supercapacitor hybrid (BSH) device has been proposed here introducing a hierarchically orientated double hydroxide assembly of cobalt tin hydroxide@nickel hydroxide (CoSn(OH)6@∝-Ni(OH)2) as positive (CTH@NH) and nitrogen, sulfur-doped reduced graphene oxide (NSG) as negative electrode. CTH@NH was obtained through few step time-dependant processes. Double shelled CTH nanocube arrays were obtained by excess alkali etching of intermediate nanocubes that are resulted from fast co-precipitation process at earlier stage. Subsequent growth of ∝-Ni(OH)2 nanoflake upon double shelled CTH nanocube at high pressure and temperature resulted CTH@NH. Improvised core-shell nanodimensional architecture, reduced particle size, mesoporosity and ample surface charges encourage diffusion mediated charge storage with deep flow facility of electrolyte into inner core of electrode material and thus strengthening charge storage capability and capacity which assured significant specific capacity (Cm) of ∼ 1467.24 C g−1 (specific capacitance (Cs): ∼ 2445 F g−1) in the hybrid much higher than CTH (Cm ∼ 480.96 C g−1, Cs of ∼ 801.7 F g−1) at 1 A g−1. The [CTH@NH//NSG] assembled BSH acquired CASC of ∼ 151.5 F g−1 at 1 A g−1 current density with a long term cycling stability of ∼ 95% even after 8000 successive charge-discharge cycles. The concurrent battery performance of CTH@NH along with supercapacitive output of the NSG overcomes the deficiency of specific energy of supercapacitor by providing an excellent specific energy of ∼ 53.8 Wh Kg−1 at a specific power of ∼ 800 W Kg−1 and instigates the high-performance features in the as-fabricated BSH device.