Design and characterization of high performance dendrite-free metallic lithium anodes for next generation batteries

Abstract

The development of next generation energy storage devices greatly rely on rechargeable high-energy batteries. Metallic lithium are considered as an ideal anode for such devices due to its ultrahigh capacity (3860 mAh$g^{-1}$), and lowest redox potential (-3.04 V vs. SHE). However, the safety concerns due to dendritic growth and low Coulombic efficiency severely hinders their commercialization. In this thesis, several engineered carbon based porous architectures including vertically aligned nanoporous carbon tubular structure (VNPCT) and 3-D microporous graphene foam (MGF) were studied as a deposition host to metallic lithium. In addition, the potential of different porous structures in alleviating the dendrite growth and improving the electrochemical performance of Li is briefly examined, and compared with planar metal deposition host. The mechanism of Li plating/stripping behavior on designed porous structures are studied through ex-situ analysis. On the other hand, highly abundant sulfur (S) cathode with high theoretical capacity is considered promising cathode for next generation batteries. Coupling sulfur cathode with lithium metal anode enable a high-energy lithium-sulfur (Li-S) battery (2600 Wh$kg^{-1}$), much superior to conventional LIBs. However, the practical applications of sulfur cathode are hindered by low sulfur utilization, polysulfide shuttle and poor life. Herein, we propose, SnS2 modified separator design to improve the kinetics of sulfur cathode by inhibiting polysulfide shuttle effect. At the end, the practical viability of Li-S full cell is demonstrated using the lithiated porous carbon anode and S cathode.