Carbon Derived from Pine Needles as a Na+-Storage Electrode Material in Dual-Ion Batteries

Pine needles are used as the precursor material to prepare hard carbon. Scanning electron microscopy, X-ray diffraction, and N-2 adsorption-desorption tests are carried out to characterize the surface, crystal, and pore structure of the material. The pine needle derived carbon (PNC) exhibits excellent Na-ion storage ability. A dual-ion battery of PNC/graphite using a Na+-based organic electrolyte is constructed. The batteries display outstanding electrochemical performance: a superior energy density (200 Wh kg(-1) at 131 W kg(-1)), high cut-off voltage (4.7 V), and outstanding cycling stability (87.2% retention after 1000 cycles). In addition, the separate responses of the cathode and anode are investigated.