Silicon micro/nanostructures are promising building blocks for high-performance solar cells, lithium-ion batteries, sensors and so on. Great challenges like high cost and complex fabrication process still exist for the fabrication of silicon micro/nanostructures, especially for the fabrication of uniformly distributed silicon micro/nanostructures. In this study, the generally unwelcome failure of materials, nanopitting, was introduced and demonstrated to be effective in micro/nanofabrication for the first time. Together with wet chemical etching, uniformly distributed silicon micro/nanostructures were obtained. Ag islands were formed by the nanopitting of chloridion, which will be used as mask and catalyser in the chemical etching process. The silicon micro/nanostructures, especially, uniformly distributed p-type silicon micro/nanostructures were fabricated with the low-cost and facile fabrication approach. In addition, the application of the silicon micro/nanostructures was demonstrated as microsupercapacitive electrodes with the integration of MnO2 nanostructures. The results show that the electrochemical performance of silicon micro/nanostructures was much better than that of silicon microstructures. The proposed approach is cost-effective to fabricate silicon micro/nanostructures, and the silicon micro/nanostructures have great potentials in miniaturised energy storage devices, sensors and photodevices.