Highly Flexible and Transferable Supercapacitors with Ordered Three-Dimensional MnO2/Au/MnO2 Nanospikes Arrays

Ordered three-dimensional nanostructures such as arrays of nanospikes, nanocones, and nanotubes naturally have large interface/surface area, which are highly attractive for energy storage application, particularly for high-performance flexible supercapacitors. Here, we report a unique MnO₂/Au/MnO₂ Nanospikes (MAMNSPs) supercapacitor structure based on ultra-thin, free-standing 3-D gold (Au) NSPs film. The NSPs films are highly flexible and transferable to arbitrary type of flexible substrate to enable applications that require high flexibility. The large surface area of this unique structure leads remarkable enhancement in electrochemical performance, 1.9 and 4.26 times capacitance as compared with MnO₂/Au NSPs (MANSPs) and MnO₂/Planar (MAPL) electrodes, respectively. The all-solid-state symmetric supercapacitors based on MAMNSPs electrodes have been fabricated and systematic performance characterizations showed that the devices have high volumetric capacitance of 20.35 F cm^-3 and specific energy of 1.75 × 10^-3 Wh cm^-3. In addition, bendability measurement showed that the supercapacitor devices are highly flexible and reliable. With virtue of simple fabrication procedures and enhanced electrochemical performance, such 3-D structures have highly promising potency for portable and flexible energy storage systems for a wide range of practical applications.