Laser-scribed phosphorus-doped graphene derived from Kevlar textile for enhanced wearable micro-supercapacitor

The development of wearable electronics has facilitated the growth of flexible energy storage systems, including micro-supercapacitors (MSCs). Thus, it is urgent to fabricate MSCs with both excellent mechanical strength and electrochemical performance. In this work, P-enriched laser-induced graphene (LIG) is fabricated for the first time on Kevlar textiles via the one-step laser direct writing process. Laser engraving is employed on polyvinyl alcohol (PVA)/H3PO4-coated Kevlar to obtain porous graphene and simultaneously in-situ dope phosphorus in pure LIG. The unreacted gel dopant could be removed by washing in hot water because of the thermal solubility of PVA, therefore the Janus LIG/Kevlar textiles keep well flexible and skin-friendly. Moreover, the phosphorus-doped LIG has optimized porous morphology compared to pure LIG, which benefits the interface between electrolyte and electrodes. The introduction of phosphorus contributes to the electrochemical performance attributed to the optimized porous morphology and pseudocapacitance brought by phosphorus doping. The obtained in-plane MSCs (PMSC-4) on Kevlar textiles present a high areal capacitance of 125.35 mF cm-2, good cycling stability (over 88% during 10,000 cycles), and flexibility. This work provides a facial and scalable method firstly to fabricate and optimize heteroatom-doping MSCs on Kevlar, showing potential for wearable electronics and electronic textiles.