Northwestern University Robert R. McCormick School of Engineering and Applied Science

Kung Research Group

Research: Electrical Energy Storage

Among the current commercial rechargeable batteries, Li ion batteries offer the highest energy density and charge capacity. However, there is a huge potential to improve their capacities significantly with new electrode materials and chemistry, both at the anode and the cathode. Some of the known high capacity materials, however, suffer from rapid degradation. Another concern is safety, especially thermal runaway that could result in battery fire. We are applying our synthetic background acquired in our study of catalytic materials to construct new forms of electrodes that could stabilize the storage components, and new components that could mitigate thermal runaway. For example, by forming a composite of silicon nanoparticles sandwiched between graphene sheets, we have demonstrated that the storage capacity can be maintained for a much longer time. By introducing in-plane defects in the graphene sheets to enhance cross-plane Li ion diffusion, the power capability is also improved significantly.  Other modification of graphene and graphene oxide could lead to further improvements, including regulating electrochemical reaction rates to reduce thermal runaway.