Lithium storage behaviors and properties of the pristine and activated catkin-derived carbon microtubes

Biomass-derived carbon materials have shown great potential for electrochemical energy storage application due to their natural abundance, high porosity, and hierarchical structure. Herein, we report the fabrication of tubular catkin-derived carbon microtubes (denote as CMTs) by directly annealing catkin in Ar, and study the effect of activation on their physicochemical characteristics as well as their lithium storage performance/behavior. The activated CMTs (a-CMTs), which are obtained by annealing pristine CMTs (p-CMTs) (436 m² g⁻¹, 0.109 cc g⁻¹) with KOH as the activating agent, display a porous structure with a high specific area (1048 m² g⁻¹) and large pore volume (0.751 cc g⁻¹). When examined as anode materials for lithium-ion batteries, both p-CMTs and a-CMTs show excellent cycling and rate performance, delivering reversible capacities of 397 and 493 mA h g⁻¹ after 400 cycles at 100 mA g⁻¹, respectively, which correspondingly show pseudocapacitive and diffusion-controlled lithium storage behaviors.