Human hair-derived carbon flakes for electrochemical supercapacitors

TLDR

High-performance supercapacitors benefit from micro/mesoporosity, large surface area, and heteroatom doping that enhance double‑layer and Faradaic storage. To develop heteroatom‑doped porous carbon flakes from human hair for use as high‑performance supercapacitor electrodes. Carbonization of human hair fibers produced heteroatom‑doped porous flakes whose morphology and composition were confirmed by electron microscopy, EDX, and XPS. The carbon flakes delivered 340 F g⁻¹ in 6 M KOH and 126 F g⁻¹ in 1 M LiPF6 EC/DEC, maintaining performance over 20 000 cycles.

Abstract

Heteroatom doped porous carbon flakes were prepared via carbonization of Chinese human hair fibers and employed for high-performance supercapacitor electrode materials. The morphology and chemical composition of the resultant carbon materials were characterized by electron microscopy (EM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) measurements. Human hair carbonized at 800 °C exhibited high charge storage capacity with a specific capacitance of 340 F g−1 in 6 M KOH at a current density of 1 A g−1 and good stability over 20 000 cycles. The specific capacitance of 126 F g−1 is also verified in a 1 M LiPF6 ethylene carbonate/diethyl carbonate (EC/DEC) organic electrolyte at a current density of 1 A g−1. The high supercapacitor performance could be due to the micro/mesoporosity combined with high effective surface area and heteroatom doping effects, combining double layer and Faradaic contributions.