Hierarchically porous nitrogen-rich carbon derived from wheat straw as an ultra-high-rate anode for lithium ion batteries

Abstract

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⁻¹ at 0.037 A g⁻¹, and possesses an ultrahigh rate capability of 344 mA h g⁻¹ at 18.5 A g⁻¹. Even at an extremely high current density of 37 A g⁻¹, the reversible capacity is still as high as 198 mA h g⁻¹.