Low-cost synthesis of sulfur doped apricot shell activated carbon material with hierarchical porous structure for flexible supercapacitor

It is significant to convert biomass waste into economical and high-performance supercapacitor materials. Herein, a series of sulfur-doped apricot shell activated carbons (S-ASAC) were economically synthesized via a readily scalable method with apricot shell wastes and MgSO₄ as carbon and sulfur sources, respectively. The obtained S-ASAC material exhibits appropriate sulfur modification and a controllable hierarchical pore structure. The optimal S-ASAC-1.5 electrode material shows a large specific capacitance of 304.6F g⁻¹, high cycle stability with 98.5 % capacitance retention after 10,000 cycles at 10 A g⁻¹ and good rate performance with capacitance retention of 72.2 % at 0.1–20 A g⁻¹, originating from the pseudocapacitance increased by sulfur species and hierarchical pore structure. The S-ASAC-1.5 was further used to construct a flexible supercapacitor with energy density of 34.62 µWh cm⁻² at a power density of 124.5 µW cm⁻², which is superior to that obtained for Mn doped NiCo₂O₄, Ni/MnO₂ supercapacitor, etc.