Because of their high energy density, low cost, and environmental friendliness, lithium−sulfur (Li−S) batteries are one of the potential candidates for the next-generation energy-storage devices. However, they have been troubled by sluggish reaction kinetics for the insoluble Li 2 S product and capacity degradation because of the severe shuttle effect of polysulfides. These problems have been overcome by introducing transition metal compounds (TMCs) as catalysts into the interlayer of modified separator or sulfur host. This review first introduces the mechanism of sulfur redox reactions. The methods for studying TMC catalysts in Li−S batteries are provided. Then, the recent advances of TMCs (such as metal oxides, metal sulfides, metal selenides, metal nitrides, metal phosphides, metal carbides, metal borides, and heterostructures) as catalysts and some helpful design and modulation strategies in Li−S batteries are highlighted and summarized. At last, future opportunities toward TMC catalysts in Li−S batteries are presented.

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Pipelines are critical for transportation of oil and gas. A Steel Strip Reinforced Thermoplastic Pipe (SSRTP) is applied in the offshore environment because of its superior mechanical performance. Due to the complex subsea conditions, SSRTP is subject to severe loading and may be damaged during its design life. The failure modes of SSRTP, related to four principle loading cases, are investigated in the FE models. The preliminary results will reveal the mechanical behavior of the critical layer of SSRTP prior to damage. An optical fiber sensor is then introduced within the SSRTP as a novel system to monitor the strain of the critical layer.