Laser-induced nitrogen-self-doped graphite nanofibers from cyanate ester for on-chip micro-supercapacitors

Abstract

The fabrication of high-content heteroatoms-doped carbon nanomaterials is crucial for energy storage. Conventional external heteroatoms-doping usually needs complex and time-consuming preparation processes. Here, we report the facile and high-efficient fabrication of high-content (10.3%) nitrogen-self-doped graphite in the form of banyan root hairs-like nanofibers by laser direct writing on nitrogen-enriched cyanate ester. The resulting laser-induced graphite nanofibers (LIGNFs) exhibit high-temperature stability up to 470 °C in air, which outperforms the laser-induced graphene (LIG), laser-sculptured carbide and MXenes. The medium power level of laser can produce high quality and uniform distributed nanofibers, while the high power level could generate root nodule-like and even agglomerated nanofibers with more effective conductive network and higher nitrogen content, leading to relatively low quality but lower sheet resistance (21.50 Ω/square). Benefiting from the reverse surface atom-controlled pseudocapacitive effect, the LIGNFs-based on-chip in-plane micro-supercapacitors (LIGNFs-IMSCs) provide a superior areal capacitance of 57.96 mF/cm2, which is about seven times as high as that of LIG-based IMSCs. Additionally, the LIGNFs-IMSCs present excellent cycling stability and nearly 100% coulombic efficiency after 12,000 cycles. The novel LIGNFs with high-efficient preparation process, high-thermal stability and excellent electrochemical performance may have promising applications for energy storage devices in extreme environments.