Superior electrochemical performance of sodium-ion full-cell using poplar wood derived hard carbon anode

As a supplement to lithium-ion batteries, the rate capability and cycling stability of sodium-ion batteries still need to be improved for practical applications. Here we report a novel poplar wood derived hard carbon anode, exhibiting a high specific capacity of 330 mAh/g and an initial Coulombic efficiency of 88.3% in half cells, and delivering a reversible specific energy of 212.9 Wh/kg (based on two-electrode masses) at 1 C and a long cycle life of 1200 cycles at 5 C when pairing with Na[Cu1/9Ni2/9Fe1/3Mn1/3]O2 cathode in full cells. In addition, with the matched areal capacity of 2 mAh/cm2 and under the industrial level cathode loading of 20.5 mg/cm2, the capacity highly maintains at 2 C, and after 1400 cycles could almost fully recover by setting the current rate to C/10. This indicates sodium-ion batteries are approaching maturity.