Printable thin film supercapacitors utilizing single crystal cobalt hydroxidenanosheets

Cobalt hydroxide (β-Co(OH)2) thin film supercapacitors are developed for the first time via screen printing and their potential application towards energy storage (as an electrode material within a supercapacitor) explored. The highly uniform, porous nanostructures were synthesized via a novel, hydrothermal, template-free approach. The nanostructures consist of amassing, arbitrarily layered, interconnecting nanosheets, resulting in a flower-like structure with many fissures. These nanostructures were fabricated into flexible thin film supercapacitors via screen printing for the first time. The β-Co(OH)2 asymmetric supercapacitor is found to deliver a maximum specific capacitance of ∼170 F g−1 at a current density of 0.5 μA in an aqueous electrolyte solution (3M KOH) retaining 99.69% of its maximum capacity over 600 cycles. Given the ability to mass produce such supercapacitors via screen printing, where readily, synthetically fabricated nanostructures can be incorporated, the application of this approach will likely be widely implemented.