Directly Deposited Binder-Free Sulfur Electrode Enabled by Air-Controlled Electrospray Process

Lithium-sulfur batteries are one of the most promising energy storage technologies to replace commercial Li-ion batteries due to 5-fold higher theoretical energy density, and lower cost. However, due to certain limitations, the technology is not ready to be deployed. To overcome some of these, scientists have been extensively employing graphene oxide (GO) or graphene material to improve the electrochemical performance. In this work, we present a unique, novel, and facile method to deposit the active materials onto an aluminum current collector by utilizing the van der Waals interaction between graphene oxide and aluminum via an air-controlled electrospray (ACES) process. The role of conventional polymer binder was replaced by graphene, resulting in a binder-free substrate. We demonstrated that the elimination of conventional polymer binder and graphene layers assembled via the ACES method resulted in higher capacity and retention, and offer almost 4 times higher capacity at 2C than the conventional slurry-cast system with polymer binder. This ACES technique offers potential for improving the overall energy density of sulfur and being adapted for commercialization in the energy storage industry.