title: Discharging a Li-S battery with ultra-high sulphur content cathode using a redox mediator.
abstract: Lithium-sulphur batteries are under intense research due to the high specific capacity and low cost. However, several problems limit their commercialization. One of them is the insulating nature of sulphur, which necessitates a large amount of conductive agent and binder in the cathode, reducing the effective sulphur load as well as the energy density. Here we introduce a redox mediator, cobaltocene, which acts as an electron transfer agent between the conductive surface and the polysulphides in the electrolyte. We confirmed that cobaltocene could effectively convert polysulphides to Li2S using scanning electron microscope, X-ray absorption near-edge structure and in-situ X-ray diffraction studies. This redox mediator enabled excellent electrochemical performance in a cathode with ultra-high sulphur content (80 wt%). It delivered 400 mAh g(-1)cathode capacity after 50 cycles, which is equivalent to 800 mAh g(-1)S in a typical cathode with 50 wt% sulphur. Furthermore, the volumetric capacity was also dramatically improved.
authors: Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, South Korea.|School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, South Korea.
authors: Kwi Ryong
authors: KR
authors: Kim
authors: Beamline Department, Pohang Accelerator Laboratory (PAL), Pohang 790-784, South Korea.
authors: Kug-Seung
authors: KS
authors: Lee
authors: Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, South Korea.|School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, South Korea.
authors: Chi-Yeong
authors: CY
authors: Ahn
authors: Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, South Korea.|School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, South Korea.
authors: Seung-Ho
authors: SH
authors: Yu
authors: Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, South Korea.|School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, South Korea.
authors: Yung-Eun
authors: YE
authors: Sung