Tea-Derived Sustainable Materials

The practical application of hard carbon in sodium-ion batteries is limited by insufficient reversible capacity and low initial Coulombic efficiency (ICE), which are caused by the lack of active sites and unstable electrode/electrolyte interface. Herein, a biomass-derived hard carbon material based on tea stems is proposed, which exhibits an ultrahigh ICE of 90.8%. This remarkable ICE is attributed to the presence of an inorganic-rich, thin, and robust solid electrolyte interface (SEI) layer. Furthermore, the material demonstrates excellent cycling stability, showing a capacity retention of 99.5% after 500 cycles at 280 mA g-1. Additionally, when it works as the anode material in a sodium-ion full cell without presodiation, it reaches a high energy density of 212 Wh kg-1 and a superior stability, e.g., retaining 93.1 mAh g-1 after 1000 cycles at 1 A g-1 with a capacity retention of 91.3%. The sodium storage capacity of this material is primarily attributed to a combined adsorption-intercalation/filling effect as confirmed by in situ XRD and ex situ Raman analyses. These findings make this biomass-derived hard carbon material a promising candidate for commercial application of sodium-ion batteries, achieving high performance at low cost. Tea-derived materials have advanced sustainable energy, environment, and biomedicine applications for circular economy, sustainability, and carbon neutrality. Biomass-derived hard carbon materials are developed based on tea, which exhibit ultrahigh performance and excellent cycling stability attributing to the inorganic-rich, thin, and robust solid interface layer and combined adsorption-intercalation/filling effects, achieving high performance at low cost for advanced commercial applications.image