Ultrathin, Wrinkled, Vertically Aligned Co(OH)₂ Nanosheets/Ag Nanowires Hybrid Network for Flexible Transparent Supercapacitor with High Performance

Abstract

Developing high-performance, flexible, transparent supercapacitors for wearable electronics represents an important challenge, as it requires active materials to be sufficiently transparent without compromising energy storage. Here, we manipulate the morphology of the active materials and the junctions on the current collector to achieve optimum electronic/ionic transport kinetics. Two-dimensional Co(OH)₂ nanosheets with single or two layers were vertically aligned onto a modified Ag nanowires (AgNWs) network using an electrochemical deposition-UV irradiation approach. The metallic AgNWs network endows high transparency while minimizing the contact resistance with the pseudocapacitive Co(OH)₂ nanosheets. The Co(OH)₂ nanosheets self-assembled into a three-dimensional array, which is beneficial for the fast ion movements. The rational materials design greatly boosts the electrochemical performance of the hybrid network, including an ultrahigh areal capacitance up to 3108 μC cm^-2 (5180 μF cm^-2) coupled with long cycle life (20 000 cycles). As a prototype device, the symmetric supercapacitor well combines high energy/power density and excellent mechanical flexibility and long-term performance, suggesting a promising application for the next-generation wearable electronics.