A dyeing-induced heteroatom-co-doped route toward flexible carbon electrode derived from silk fabric

Flexible carbon electrode with high performance from silk fabric was fabricated by a simple approach. Silk fabric was uniformly dyed with heteroatom-enriched dye molecules by a traditional dyeing process, followed by direct pyrolysis. The as-prepared heteroatom-co-doped carbonized silk fabric exhibits a significantly improved electrochemical performance with the specific capacitance of 255.95 F g⁻¹ at the scan rate of 2 mV s⁻¹ using 1 M Na₂SO₄ electrolyte, a wide operation voltage window as well as a good cycling life stability (8% capacitance loss over 5000 cycles). The excellent capacitive performance can be attributed to the multiple synergistic effects between the double-layer capacitance (hierarchical porosity, good wettability and conductivity) and the extra pseudocapacitance (N, O and S heteroatom co-doping). Moreover, the carbonized dyed silk fabric possesses wearability and lightweight. Importantly, the convenient approach can provide industrial-grade production of heteroatom-co-doped silk fabric-based carbon electrode materials for applications in flexible energy storage devices.