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Poly(ethylene oxide)-coated sulfur/carbon (S/C/PEO) composite with a high sulfur loading is prepared to improve the performance of lithium-sulfur batteries. By magnetic string, 3.7 wt% PEO is coated onto the surface of ball-milling obtained S/C composite, leading to synthesis of S/C/PEO composite containing 78 wt% S. It is confirmed from a series of measurements that PEO covers the S/C composite uniformly, and PEO coating is quite effective in stabilizing the electrochemical performance. When employed as cathode for lithium-sulfur batteries, S/C/PEO delivers an initial discharge capacity of 989.6 mAh g and remains 648.3 mAh g after 110 cycles at a discharge/charge rate of 1 C (based on sulfur weight). Meanwhile, the coulomb efficiency of S/C/PEO composite reaches to ~98 % during the latter 105 cycles. The improved electrochemical performance can be attributed to the formation of PEO coating layer which can keep a tight contact between carbon and sulfur and lead to improved conductivity. Moreover, the PEO coating can act as a flexible cushion to accommodate volume changes of sulfur cathode as well as a barrier to trap soluble polysulfide intermediates during the charge-discharge processes. [ABSTRACT FROM AUTHOR]

To simulate self-irradiation effects of nuclear waste forms in long period of deep geological disposal, Gd2Ce2O7 as simulated An4+ matrix was chosen to be irradiated using 0.5 MeV alpha ions to fluences ranging from 1 × 1015 to 1 × 1017 ions cm−2. Irradiation-induced structural change and microstructural evolution were examined using grazing incidence X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Lattice swelling and amorphization in irradiated layer indicated an enhanced disordering degree with increased ion fluences. Main Raman peaks broaden and intensity decrease indicated a significant bonds distortion. In addition, no element aggregation about Gd, Ce and O occurs after He2+ irradiation. [ABSTRACT FROM AUTHOR]

In this paper, a sol-spray pyrolysis route was employed to fabricate (Cs, Ba)-hollandite ceramic waste forms. The high-phase purity (Cs0.8−xBa0.4+x)(Al1.6+xTi6.4−x)O16 (0 ≤ x ≤ 0.4) ceramics were synthesized at 1050 °C using the produced powders by sol-spray pyrolysis. The results show that all samples show tetragonal hollandite with rod morphology. Additionally, the sintered (Cs, Ba)-hollandite ceramics exhibit a good chemical durability. The normalized release rates of Cs and Ba were < 10−2 g m−2 d−1 after 14 days. These results indicate that hollandite ceramics are promising candidate for immobilizing radioactive cesium. [ABSTRACT FROM AUTHOR]