Fabrication of ZIF-67 Derived Co3S4-WS2 Heterostructures for All-Solid-State Symmetrical Supercapacitors

Abstract

Development and modification of the existing material for renewable energy area is gaining its significance however a long way to get commercialization. Transition metal dichalcogenides (TMDs) are gaining interest rapidly in the field of supercapacitors due to their 2D layered morphology, however loses interest for long cyclic stability. Herein we employed hollow Co3S4 microspheres using nitrogen rich ZIF-67 as a precursor. Furthermore, these hollow Co3S4 microspheres are insitu modified by covering with WS2 nanostructures to enhance its energy density. The obtained Co3S4/WS2 composite when employed as an electrode, delivers the specific capacitance of 412.7 F/g at the current density of 1 A/g. Furthermore, the Co3S4/WS2 composite electrodes are used to fabricate an all solid-state symmetrical supercapacitor device, exhibiting a wide potential window of 2 V. The assembled device delivers a very high energy density of 70.7 Wh/kg along with a high-power density of 10.2 kW/kg. The excellent electrochemical performance with 92 % capacity retention proves its potential toward the practical application. The high value of specific capacitance and splendid cycle stability is attributed to the synergy of high surface area ZIF-67 derived Co3S4 microsphere with 2D networked WS2 material.