A method for the fabrication of h-WO3/WS2 core/shell nanowires and their use in flexible supercapacitor applications. The novel nanowire assemblies exhibit multifold advantages desired for high-performance supercapacitors, including superior material properties and electrode design. The material design principle can be extended to other material systems, implying its great potential for a variety of energy storage devices compatible with emerging flexible and wearable technologies.