Free-standing and flexible graphene supercapacitors of high areal capacitance fabricated by laser holography reduction of graphene oxide

Photoreduction of graphene oxide (GO) holds great potential for developing graphene-based electrodes for high-performance supercapacitors (SCs). However, the insufficient micro-nanostructure on photoreduced GO (PRGO) restricts its electrochemical performance. Here, a hierarchically structured PRGO-based planar SC is reported by combining two-beam-laser-interference with the masking technique. The hierarchical structures improve the surface area between PRGO and electrolyte and contribute to format electric double-layer capacitors. Planar device structures with PRGO-based interdigital finger current collectors are beneficial for rapid ion diffusion paths. As a result, the hierarchically structured PRGO-based planar SC achieves an areal capacitance of 3.97 mF cm−2 at 10 mV s−1. The proposed strategy of employing hierarchically structured PRGO in the planar SC design offers a new route for manufacturing high-performance integrated energy storage devices.