Search

As a widely used electrocatalyst in fuel cells, metallic platinum has achieved great success in terms of kinetic promotion. Still plagued by a familiar problem, owing to the sluggish kinetics of irreversible Li2S2/Li2S species deposition, lithium−sulfur batteries with high theoretical energy are far from being realized. Inspired by the similarity between oxygen and sulfur, being in the same group, commercially available Pt/C was investigated here to explore the possible effect on the sulfur cathode. The electrochemical tests show that the electrode with 2 wt% Pt added delivers a 61 % enhancement in the discharging specific capacity compared to the control electrode after 200 cycles at 0.5 C, along with an average coulombic efficiency of 98.3 %. It is proven that these beneficial results can be attributed to the favorable capability of polysulfide immobilization and effective inhibition of self-discharging behavior. The ex situ XPS analysis and the increased exchange current density further reveal that the involved platinum nanoparticles could not only function as a static chemical absorber for polysulfide species, but, more importantly, to promote the redox kinetic effectively as an electrochemical catalyst. The positive effect of utilizing commercial Pt/C materials directly on sulfur cathodes is of great significance in developing sulfur cathodes for Li/S batteries. [ABSTRACT FROM AUTHOR]

Spent sulfidic caustics (SSC) from caustic desulfurization are toxic hazards to the environment and humans. A new one-step process is proposed firstly to decrease the concentration of SSC and to assemble a high-performance sulfur cathode synchronously by electrolyzing a simulating solution with flexible carbon felt (CF) at 15 mA cm−2. The CF that electrolyzed for 8 hours with a sulfur content of 36.6 wt % or 5.63 mgsulfur cm−2 stands out from three S/CF composites in terms of areal capacity and cycling stability. XRD, TEM, thermogravimetric analysis, and Raman spectroscopy were then used to characterize the materials. Values of 4.03 mA h cm−2 over 150 cycles at 0.2 C and 2.34 mA h cm−2 after 90 cycles at 0.5 C can be attributed to an appropriate ratio of the external/inner sulfur content. The beneficial results prove the feasibility of an innovative mode of 'pollutant disposal with synchronous application', which integrates environmental management with the development of storage energy materials efficiently and eliminates the tedious individual disposal of pollutants and preparation of slurry-derived sulfur cathodes. [ABSTRACT FROM AUTHOR]

Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies due to their high theoretical specific energy of 1675 mAh g −1 . However, the rapid capacity degradation, mainly caused by polysulfide dissolution, remains a significant challenge prior to practical applications. In this work, a sulfur cathode modified by bifunctional nafion/γ-Al 2 O 3 membrane has been successfully prepared, which can remarkably immobilize the polysulfides within the unique cathode structure due to its ions selectivity and absorbent capacity. A high initial discharge capacity of 1448.0 mAh g −1 can be achieved at 1C and 788.6 mAh g −1 preserved after 200 cycles, indicating a slow degradation. Furthermore, the coulombic efficiency maintains as high as 97% during cycling. The excellent electrochemical properties can be attributed to the bifunctional and stable membrane which can dramatically reduce the shuttle effect and keep integrated even after charging–discharging for 200 cycles. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a nafion coated electrode is prepared to improve the performance of lithium sulfur batteries. It is demonstrated from a series of measurements that the nafion layer is quite effective in reducing shuttle effect and enhancing the stability and the reversibility of the electrode. When measured under the rate of 0.2 C, the initial discharge capacity of the nafion coated electrode can reach 1084 mAh g−1, with a Columbic efficiency of about 100%. After 100 charge/discharge cycles, this electrode can also deliver a reversible capacity of as high as 879 mAh g−1. Significantly, the charge-transfer resistance of the electrode tends to be reducing after coated with an appropriate thickness of nafion film. The cation conductivity as well as anion inconductivity is considered to be the dominant factor for the superior electrochemical properties. [Copyright &y& Elsevier]

Turning stone into gold: The cover image depicts a green and efficient route to convert spent sulfidic caustic (SSC) into advanced energy‐storage materials. Compared with the conventional methods to transform sulfide separately, the novel strategy to recycle sulfide from SSC is particularly striking, not only decreasing the polluting sulfide successfully, but also simultaneously fabricating a sulfur/carbon composite for lithium–sulfur batteries. The composite with the appropriate inner/external ratio of sulfur content exhibited excellent areal capacity and good cycling performance. These excellent results prove the feasibility of an innovative method of “pollutant disposal with synchronization application”, which integrates environmental management with storage‐energy‐material development efficiently, replacing the tedious methods of disposing of pollutant and preparing the slurry‐derived sulfur cathode individually. More details can be found in the Full Paper by Wenlong Huang and Zhongqiang Shan et al. from Tianjin(Peiyang) University of China on page 1282 in Issue 8, 2017 (DOI: 10.1002/ente.201600611). [ABSTRACT FROM AUTHOR]