Recycling of waste coal-based filter materials into carbon anode materials for potassium and sodium-ion batteries

Abstract

Recycling waste resources into electrode materials for energy storage is crucial for achieving sustainable societal advancements. In industrial production, anthracite can be employed as a filter material following the annealing process, which effectively reduces the ash content and facilitates the growth of nanographite-like domains within the material. In this work, waste coal-based filter materials are recycled into carbon anode materials for potassium and sodium-ion batteries through a simple pickling process. Mixed acid treatment is used to remove the impurities in the waste filter material without damaging the nanographite-like domain. The nanographite-like domains offer active sites for K+ insertion, while the stacked structure of these domains generates a large number of closed pores for Na+ pore filling. Additionally, the numerous grain boundaries facilitate rapid ion diffusion. When the waste filter material derived carbon is used as anode material for PIBs, it can display a reversible potassium storage capacity of 258.8 mAh/g at 0.05 A/g. For SIBs, it exhibits the reversible capacity of 247.2 mAh/g with an obvious platform at low voltage at 0.02 A/g. A sodium-ion full battery is assembled with WFC-1800 and Na3V2(PO4)3 as electrodes, exhibiting an energy density of 179.08 Wh/kg. These findings provide a new approach to tackle the challenge of coal-based waste utilization and promote progress in the field of large-scale storage applications.