Ultra-stable sodium ion storage of biomass porous carbon derived from sugarcane

Development of low-cost anode for sodium-ion battery (NIB) has become the most desirable target in today's energy demanding society. In this work, we present different treatments of sugarcane biomass to alter the lignocellulose compositions to obtain low-cost porous carbon as NIB's anode. The optimized sugarcane biomass derived carbon presents the initial reversible capacity of 229 mAh g−1 and the reversible capacity of 189 mAh g−1 at 100 mA g−1 after 50 cycles. It is worth noting that the carbon also exhibits an extremely low voltage plateau with 74.2 % of discharge capacity originating from the voltages below 0.5 V. In addition, the sugarcane biomass derived carbon displays an ultra-stable capacity with almost no attenuation even after 2000 cycles. In consideration of the low voltage plateau, we also calculated the relative energy density (ER, combination of the capacity and voltage plateau), and a high ER of 500 Wh kg−1 in the first cycle and 416 Wh kg−1 after 50 cycles are obtained. In situ TEM analysis was conducted to investigate the structural stability of sugarcane biomass derived carbon. Small volumetric changes are observed at different charge-discharge states, indicating the structural stability of our sugarcane biomass derived carbon during sodiation-desodiation process, which is conducive to the stable cycling of Na-ions.