Sustainable core-shell structures derived from lignin for Na ion batteries

The aromatic nature of the structure of lignin enables its use as a natural and sustainable hard carbon precursor. Upon carbonisation, lignin-derived hard carbon has shown potential as a sodium-ion battery anode. In this study, we have utilised coaxial electrospinning to produce nanofibers, which undergo stabilisation and carbonisation, to analyse the influence of carbon morphology on sodium-ion storage mechanisms. Various nanostructures have been tailored to produce intricate core/shell structures with varying degrees of porosity to allow controlled Na diffusion and storage. The morphology of these unique high surface area nanostructures has been assessed by scanning electron microscopy. The optimized Core-Shell structure shows a specific capacity of 184.7mAh g^-1, with 99.7 % of coulombic efficiency. This innovative and green approach enables new strategies to obtain sustainable materials for sodium ion energy storage applications.