No abstract

The OHC shows superior performance as an anode material for LIBs with a high reversible capacity (1181 mA h g−1 at 0.1 A g−1) and an excellent rate capability (304 mA h g−1 at 5 A g−1).

A facile, economical and effective method to produce hierarchically porous nitrogen-rich carbon (HPNC) from wheat straw has been reported. Acid pretreatment is introduced before KOH activation, and plays the role of promoting the formation of thinner pore walls. Without any N-doping, the N content is as high as 5.13%. The HPNC when used as an anode for Li-ion batteries exhibits a superior specific capacity of 1470 mA h g À1 at 0.037 A g À1 , and possesses an ultrahigh rate capability of 344 mA h g À1 at 18.5 A g À1 . Even at an extremely high current density of 37 A g À1 , the reversible capacity is still as high as 198 mA h g À1 .