title: Hierarchical porous carbon by ultrasonic spray pyrolysis yields stable cycling in lithium-sulfur battery.
abstract: Utilizing the unparalleled theoretical capacity of sulfur reaching 1675 mAh/g, lithium-sulfur (Li-S) batteries have been counted as promising enablers of future lithium ion battery (LIB) applications requiring high energy densities. Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from dissolution of lithium polysulfides. As a fundamental solution to this chronic shortcoming, herein, we introduce a hierarchical porous carbon structure in which meso- and macropores are surrounded by outer micropores. Sulfur was infiltrated mainly into the inner meso- and macropores, while the outer micropores remained empty, thus serving as a "barricade" against outward dissolution of long-chain lithium polysulfides. On the basis of this systematic design, the sulfur electrode delivered 1412 mAh/g sulfur with excellent capacity retention of 77% after 500 cycles. Also, a control study suggests that even when sulfur is loaded into the outer micropores, the robust cycling performance is preserved by engaging small sulfur crystal structures (S2-4). Furthermore, the hierarchical porous carbon was produced in ultrahigh speed by scalable spray pyrolysis. Each porous carbon particle was synthesized through 5 s of carrier gas flow in a reaction tube.
authors.affiliation: Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and Center for Nature-inspired Technology (CNiT), KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehakro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Dae Soo
authors.initials: DS
authors.lastname: Jung
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Hwang
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Koo
authors.forename: Rana A
authors.initials: RA
authors.lastname: Shakoor
authors.forename: Ramazan
authors.initials: R
authors.lastname: Kahraman
authors.forename: Yong Nam
authors.initials: YN
authors.lastname: Jo
authors.forename: Min-Sik
authors.initials: MS
authors.lastname: Park
authors.forename: Jang Wook
authors.initials: JW
authors.lastname: Choi