Microporous bamboo biochar for lithium-sulfur batteries

Being simple, inexpensive, scalable and environmentally friendly, microporous biomass biochars have been attracting enthusiastic attention for application in lithium-sulfur （Li-S） batteries. Herein, porous bamboo biochar is activated via a KOH/annealing process that creates a microporous structure, boosts surface area and enhances electronic conductivity. The treated sample is used to encapsulate sulfur to prepare a microporous bamboo carbon-sulfur （BC-S） nanocomposite for use as the cathode for Li-S batteries for the first time. The BC-S nanocomposite with 50 wt.% sulfur content delivers a high initial capacity of 1,295 mA-h/g at a low discharge rate of 160 mA/g and high capacity retention of 550 mA-h/g after 150 cycles at a high discharge rate of 800 mA/g with excellent coulombic efficiency （995%）. This suggests that the BC-S nanocomposite could be a promising cathode material for Li-S batteries.