▎ 摘　　要

Supercapacitors are devices that instantly store and release electrical energy. However, their applications have been severely impeded by low capacitances under high operating voltages due to the surface area limit. This is why supercapacitors have not been applied for energy storage as widely as capacitors. Here, we present an innovative concept of subwavelength-featured graphene supercapacitor arrays fabricated by induction-inhibition femtosecond laser scribing. A graphene oxide film containing water is exposed to a femtosecond laser beam to create the interdigital electrodes of reduced graphene oxide. The presence of water tunes the power threshold of graphene oxide photoreduction by the generation of oxygen molecules and thus inhibits the reduction. A minimum reduced graphene oxide linewidth of 95 nm is achieved, in which the diffraction limit barrier is broken. The supercapacitor exhibits outstanding performances, including an areal capacitance of 91 mF/cm2 and a gravimetric capacitance of 384 F/g. The gravimetric capacitance value is significantly higher than those for reported sandwich-type and interdigital polyimide-reduced graphene supercapacitors. Once the subwavelength-featured supercapacitors are connected in series, 10, 25, and 50 V supercapacitor arrays demonstrate capacitances of 1.8, 0.48, and 0.17 mu F, which are dramatically larger than those of capacitors (around 0.1 mu F) under the same operating voltages and device areas. The retention of the areal capacitance of the 10 V supercapacitor array is 93.9% after 10,000 cycles at a current of 0.1 mu A, exhibiting a considerable cycling stability. Moreover, the ultrafine structure shows a high stability to mechanical cycling. The capacitance retention is around 98.5% after 10,000 folding cycles. The capacitances beyond those of high-voltage capacitors pave the way toward the realization of supercapacitors as mainstream energy storage devices.