Scotch Pine Cones-Derived Hard Carbon as an Anode Material for Sodium-Ion Battery Applications

High Resolution Image Download MS PowerPoint Slide A biobased anode material for sodium-ion batteries (SIBs) was prepared through the simple pyrolysis of Scotch pine cones ( Pinus sylvestris, SPC), followed by a heteroatom doping modification. The resulting nitrogen-doped hard carbon exhibited a high reversible capacity of 273 mA·h·g –1 at a current density of 25 mA·g –1 compared to the undoped material (197 mA·h·g –1 ). X-ray diffraction analysis shows that the produced hard carbon from the biomass is highly amorphous in nature, and high-resolution transmission electron microscopy images reveal the presence of localized graphite-like structures that are found to be beneficial for the storage and transport of Na + ions during charging/discharging. Experimental results demonstrated that the increased specific surface area ( S BET = 424 m 2 ·g –1 ), high micropore volume (0.177 cm 3 ·g –1 ), and expanded interlayer spacing (>3.7 Å) and a high Na + -ion diffusion coefficient (3.08 × 10 –16 cm 2 ·s –1 ) facilitated the diffusion of sodium ions, leading to a high capacity retention of 80% after 250 cycles for the SPC-N material over the undoped one, SPC (71%). This study highlights the potential of low-cost, widely available biobased Scotch pine cones as an alternative anode material to enhance the sustainability of SIB production.