Waste-to-wealth: low-cost hard carbon anode derived from unburned charcoal with high capacity and long cycle life for sodium-ion/lithium-ion batteries

Over the past years, the biomass-derived materials are receiving more and more attention as high-performance and low-cost anodes for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). Herein, the hard carbon derived from unburned charcoal (UC-x) is prepared by acid and heat treatment. And it is inferred from morphological characterization that the unique net structure is favorable for electrolyte permeation and charge transfer for Na+/Li+. As a result, the UC-x electrode as an anode shows high specific capacity (150 m Ah g − 1 for SIBs and 350 m A h g − 1 for LIBs at 0.1 A g − 1) and enhanced cycling stability (250 mA h g − 1 after 300 cycles for LIBs and 273 mA h g − 1 after 200 cycles for SIBs). In addition, UC-1200 possesses fast electrochemical kinetics for Na+/Li+ (1–6 × 10−10 cm2 s − 1 for Na+ and 1–2.5 × 10−10 cm2 s − 1 for Li+) and the dominated electrode reaction is mainly controlled by pseudocapacitance. In a word, this work provides a kind of unique biomass material as anodes for SIBs/LIBs from the reutilization of the waste and promotes the development of carbonaceous electrode materials.