Ginger-derived hierarchical porous carbon as an anode material for potassium-ion batteries and capacitors

Abstract

Carbonaceous materials are ideal as an anode for potassium-ion batteries (KIBs) because of their low cost, tunable physiochemical properties, and excellent reversible intercalation of potassium-ions (K⁺). In this work, we propose for the first time an economically viable and environmentally friendly route for producing hierarchical nanoporous activated ginger-derived carbon (AGC). Large interlayer spacing with a disordered microstructure of AGC provides a reason to investigate it as a high-capacity anode for rechargeable KIBs. AGC exhibits excellent electrochemical characteristics under moderate (100 mA g⁻¹) to high rate (1000 mA g⁻¹) discharge conditions. Against a current density of 100 mA g⁻¹, a steady-state reversible capacity of 220 mA h g⁻¹ was delivered. Furthermore, a 175 mA h g⁻¹ capacity has been demonstrated at a 1000 mA g⁻¹ rate for an impressive 1000 cycles. Another striking feature of AGC is its high surface area of 2717 m² g⁻¹ which makes it a potential candidate as an electrode for constructing a potassium-ion capacitor (KIC). AGC was used as a negative electrode while activated candle soot (ACS) as the positive electrode to develop a dual carbon KIC with high-rate capability. The as developed dual carbon KIC delivered a reversible capacity of 120 mA h g⁻¹ over 100 cycles at 50 mA g⁻¹. In essence, due to the extraordinary physiochemical characteristics, AGC is therefore not only a superior electrode material to other biomass-derived carbons but also a viable contender for various other electroactive applications.