Sustainable, inexpensive, naturally multi-functionalized biomass carbon for both Li metal anode and sulfur cathode

Lithium sulfur (Li-S) battery has been regarded as the promising energy storage device. However, this technology faces great challenges from both anode and cathode, which are mainly caused by the nature of materials. Here, we report a kind of multifunctional carbon derived from biomass like rice husk for optimizing both lithium (Li) metal anode and sulfur (S) cathode for Li-S batteries. It has been proved that the surface functionalized rice husk derived carbon could effectively achieve the controllable deposition of Li. Notably, the nucleation overpotential is reduced and the Coulombic efficiency is also improved. As for the cathode, the biomass carbon with high specific surface area and natural SiO2 nanoparticles is benificial for confining sulfur and sulfides. As a result, when the modified Li metal anode paired with carbon/sulfur composite, the battery delivers improved discharge capacity, rate capability and cycling stability. Moreover, the overpotential between charge and discharge process in Li-S batteries is obviously lowered compared with bare Li foil. This novel and straightforward design via employing sustainable biomass for constructing both anode and cathode materials may do great help to achieve the commercialization of Li-S batteries.