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[Formula: see text]mAh[Formula: see text]g[Formula: see text] and a reversible capacity of 134[Formula: see text]mAh[Formula: see text]g[Formula: see text] after 300 cycles at 100[Formula: see text]mA[Formula: see text]g[Formula: see text]. Electrochemical mechanism analysis reveals a capacitive dominating Na[Formula: see text] storage process.