PDF Publication Title:
Text from PDF Page: 002
Journal of Materials Chemistry A PAPER Cite this: DOI: 10.1039/c7ta08768c View Article Online View Journal Supercritical CO2 mediated incorporation of sulfur into carbon matrix as cathode materials towards high-performance lithium–sulfur batteries† Ruyi Fang,‡a Chu Liang,‡a Yang Xia,*a Zhen Xiao,b Hui Huang,a Yongping Gan,a Jun Zhang,a Xinyong Tao a and Wenkui Zhang *a Lithium–sulfur (Li–S) batteries are considered among the most promising candidates for the next- generation electrochemical power sources. The incorporation of sulfur and carbon matrices is the most appropriate strategy to contain sulfur and suppress the soluble polysulfide shuttle. However, in the conventional methods including mechanical mixing, heat treatment and wet-chemistry synthesis, it is very difficult to guarantee the precise sulfur content, uniform sulfur distribution, and strong interaction between sulfur and carbon. Hence, a novel synthetic strategy that utilizes supercritical CO2 (SC-CO2) to fabricate C@S composites for Li–S batteries has been successfully developed. Taking the advantages of high infiltrability, excellent diffusivity and superior solvability, SC-CO2 not only serves as an intercalator that penetrates into the pores and interlayers of carbon matrices to expand/exfoliate the porous structure and tightly-stacked layered graphite structure, but also plays the role of a marvellous hydrophobic solvent to dissolve sulfur and transfer it into the inner pores and interlayers of carbon matrices. Taking AC@S as an example, it exhibits the highly reversible capacity of 817 mA h g1 after 100 cycles at 0.1 A g1, and excellent cycling stability with a satisfactory capacity retention of 90.5%. We believe that this novel strategy will open up the prospects for synthesizing more efficient C/S composites to suppress the diffusion of polysulfides and enhance the structural stability and reaction kinetics of the sulfur cathode. Received 5th October 2017 Accepted 24th November 2017 DOI: 10.1039/c7ta08768c rsc.li/materials-a 1. Introduction Rechargeable batteries are crucial for the fast-growing demands of various applications including consumer electronics, electric vehicles and grid-scale stationary storage systems.1 However, the high cost and low energy density of commercial lithium-ion batteries (LIBs) consisting of a transition-metal oxide cathode and graphite anode are major obstacles to fullling the large- scale applications of electric vehicles and smart grids,2 and aCollege of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, 310014, China. E-mail: nanoshine@zjut.edu.cn; msechem@zjut.edu.cn bCollege of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China † Electronic supplementary information (ESI) available: SEM images and volume changes of MCMB, MCMB-CO2, MCMB@S, MWCNTs, MWCNTs-CO2 and MWCNTs@S samples; TEM, HRTEM images and XRD patterns of MWCNTs, MWCNTs-CO2 and MWCNTs@S samples; XRD, Raman, N2 adsorption–desorption, TEM and HRTEM analysis of MCMB and MCMB@S; STEM, EDS spectrum and EDS mapping of MCMB@S; apparent density of raw C, C–CO2 and C@S samples; long-term cycling performance of AC@C, MCMB@ S, MWCNTs@S, AC/S-155, MCMB/S-155 and MWCNTs/S-155 samples; N2 adsorption–desorption curve and pore size distribution of the cycled AC@S sample; CV curves of AC@S sample washed by CS2 at a scan rate of 0.1 mV s1. See DOI: 10.1039/c7ta08768c ‡ These authors contributed equally to this work. tremendous efforts have been made to explore new battery systems in recent years. In this respect, the lithium–sulfur (Li–S) battery with high theoretical energy density (2600 W h kg1), low cost and good environmental benignity is considered as one of the most promising candidates for the next-generation of electrochemical power sources.1,3 Nonetheless, investigations on Li–S batteries are still at the lab stage, compared to LIBs, and several fundamental issues need to be overcome before their commercialization, particularly for the sulfur cathode. (i) Unlike the transition-metal oxide cathode in conventional LIBs, the sulfur cathode involves a multi-electron-transfer electro- chemical process that is based on the conversion reaction of S8 + 16Li+ + 16e / 8Li2S.4,5 Although sulfur can electro- chemically react with lithium and provide a high theoretical specic capacity of 1675 mA h g1, sulfur and its nal products of Li2S/Li2S2 are both insulators, leading to poor electro- chemical activity and inferior specic capacity. (ii) In the discharging process, a series of intermediate products of long- chain polysuldes (Li2Sn, 4 # n # 8) are dissolved into the liquid electrolyte,6,7 and these soluble polysuldes shuttle between the sulfur cathode and lithium anode, resulting the continuous loss of active material, serious surface passivation of lithium anode and poor coulombic efficiency.8–10 This journal is © The Royal Society of Chemistry 2017 J. Mater. Chem. A Published on 24 November 2017. Downloaded by University of Texas Libraries on 08/12/2017 20:16:36.PDF Image | Supercritical CO2 Mediated Incorporation of Sulfur into Carbon Matrix
PDF Search Title:
Supercritical CO2 Mediated Incorporation of Sulfur into Carbon MatrixOriginal File Name Searched:
SupercriticalCO2mediatedincorporationofsulfurintocarbonmatrixascathodematerialstowardshigh-performancelithiumsulfurbatteries.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |