Intrinsic Defect-Rich Hierarchically Porous Carbon Architectures Enabling Enhanced Capture and Catalytic Conversion of Polysulfides.

Despite their promising potential, the real performance of lithium-sulfur batteries is still heavily impeded by the notorious shuttle behavior and sluggish conversion of polysulfides. Complex structures with multiple components have been widely employed to address these issues by virtue of their strong polarity and abundant surface catalytic sites. Nevertheless, the tedious constructing procedures and high cost of these materials make the exploration of alternative high-performance sulfur hosts increasingly important. Herein, we report an intrinsic defect-rich hierarchically porous carbon architecture with strong affinity and high conversion activity toward polysulfides even at high sulfur loading. Such an architecture can be prepared using a widely available nitrogen-containing precursor through a simple yet effective in situ templating strategy and subsequent nitrogen removal procedure. The hierarchical structure secures a high sulfur loading, while the intrinsic defects strongly anchor the active species and boost their chemical conversion because of the strong polarity and accelerated electron transfer at the defective sites. As a result, the lithium-sulfur batteries with this carbon material as the sulfur host deliver a high specific capacity of 1182 mAh g-1 at 0.5 C, excellent cycling stability with a capacity retention of 70% after 500 cycles, and outstanding rate capability, one of the best results among pure carbon hosts. The strategy suggested here may rekindle interest in exploring the potential of pure carbon materials for lithium-sulfur batteries as well as other energy storage devices.

[Study on the effect of weitongning on epidermal growth factor and nitric oxide contents in tissue of stomach of rats with gastric ulcer].

OBJECTIVE: To study the therapeutic mechanism of weitongning (WTN) in treating peptic ulcer. METHODS: Rat model of chronic gastric ulcer induced by glacial acetic acid was used to observe the effect of WTN on the curative quality, thickness of regenerated mucous membrane, epidermal growth factor (EGF) and nitric oxide (NO) contents in scar tissue around the gastric ulcer. RESULTS: The thickness of regenerated mucous membrane, EGF and NO contents in peri-ulcer scar tissue were higher in the model rats after WTN treatment than that in the untreated model rats (P<0.01 or P<0.05). CONCLUSION: WTN could elevate the quality of ulcer curing, to raise the EGF and NO contents in peri-ulcer scar tissue might be one of its mechanisms for preventing relapse of peptic ulcer.