A flexible fiber-shaped supercapacitor utilizing hierarchical NiCo2O4@polypyrrole core–shell nanowires on hemp-derived carbon

Abstract

A high-performance fiber-shaped electrode composed of hierarchical NiCo₂O₄@polypyrrole core–shell nanowires on hemp-derived carbon (HDC) microfiber is successfully fabricated, which takes advantage of the high electrical conductivity of polypyrrole and carbon microfiber to boost the pseudocapacitive performance. The as-synthesized electrode exhibits an ultrahigh specific capacitance of 2055 F g⁻¹, excellent rate performance and outstanding cycling stability (90% capacity retention over 5000 cycles). Based on the good mechanical flexibility and stability of the HDC, a fiber-shaped all-solid-state symmetric supercapacitor is designed which demonstrates a high energy density of 17.5 W h kg⁻¹ at a power density of 500 W kg⁻¹, good stability over 10 000 cycles and high physical flexibility.