Lithium-sulfur (Li-S) batteries have received great attention as a next lithium ion battery (LIB) candidate to power future applications requiring high energy densities, as the theoretical capacity of sulfur is as high as 1675 mAh/g.  Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from dissolution of lithium polysulfides and large volume change. In this presentation, I will present a hierarchical porous carbon structure in which meso- and macro-pores are surrounded by outer micropores as a fundamental solution to the chronic shortcomings of conventional Li-S batteries. Sulfur was loaded mainly into the inner meso- and macro-pores, while the outer micropores remained empty. These micropores serve as a �barricade� to inhibit outward dissolution of long-chain lithium polysulfides. Based on this systematic design, the sulfur electrode showed a specific capacity of 1412 mAh/gsulfur with stable cycling performance such as 81% capacity retention for 500 cycles. Also, a control study indicates that even when sulfur is loaded solely into the outer micropores, the robust cycling performance is maintained by engaging small allotropic sulfur crystal structures (S2-4). Moreover, ultra-fast and scalable spray pyrolysis was used for synthesis of the hierarchical porous carbon structure. Each porous carbon particle was generated after 5 seconds of carrier gas flow in a reaction tube.

Hierarchical porous carbon structure for high lithium-sulfur battery

248th National Meeting (2014)

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