Phoenix tree leaves-derived biomass carbons for sodium-ion batteries

The biomass carbons with highly developed porosity were prepared by carbonization of phoenix tree leaves (PTLs) followed by activation with KOH. The as-prepared carbons possess large interlayer spacing, abundant oxygen-containing functional groups and high degree of structural disorder. The PTLs derived carbons were firstly employed as anodes for sodium-ion batteries, with the optimized material delivering an initial discharge capacity as high as 602 mAh g^-1 and a reversible capacity of 134 mAh g^-1 after 300 cycles at 100 mA g^-1. Electrochemical mechanism analysis reveals a capacitive dominating Na⁺ storage process.