Watermelon Flesh-Like Ni3 S2 @C Composite Separator with Polysulfide Shuttle Inhibition for High-Performance Lithium-Sulfur Batteries.

The shuttle effect limits the practical application of lithium-sulfur (Li-S) batteries with high specific capacity and cheap price. Herein, a three-dimensional carbon substrate containing Ni3 S2 nanoparticles is created to modify the separator. The in situ optical visualization battery proves that the material can realize the rapid conversion of Li2 S6 . Moreover, the impact of lithium-ion diffusion on the reactions in the cell is investigated, and the mechanism of Ni3 S2 @C in the cell is proposed based on the "adsorption-diffusion-conversion" mechanism. The "adsorption-diffusion-conversion" process of polysulfide is carried out on the surface of the composite separator, showing positive effects on the inhibition of polysulfide shuttle and the promotion of conversion. The separator is modified to improve sulfur utilization and reduce dead sulfur accumulation through a strategy of chemical immobilization and physical blocking. This helps to bridge the existing gaps of Li-S batteries.

Using model texts as a type of feedback in EFL writing.

Recent work has established that model texts could be employed as a useful feedback technique. However, few studies have employed argumentative writing tasks and analyzed draft quality, and little is known about the role played by the language analytic ability in using model texts. The current study aimed to investigate what Chinese EFL learners (n = 60) noticed at the composition and comparison (comparing their texts with model texts) processes in a four-stage argumentative writing task and explore to what degree model texts can enhance the learners' subsequent writing. The four stages were: (1) writing (pre-test); (2) comparing (treatment); (3) rewriting (immediate post-test); (4) delayed writing (delayed post-test). The findings showed that learners primarily noticed lexical features in the composition and comparison stages. Higher language analytic ability (LAA) learners and guided noticing learners could notice and elicit more information from the model texts. Overall, the use of model texts was effective in improving learners' writing by providing alternative elements associated with lexis, grammar, content, and organization. In addition, the beneficial effect of model texts on writing could be maintained after 1 week. Some pedagogical implications are put forward to help teachers make better use of model texts to improve learners' writing. This study also provides new insights into how language analytic ability affects the effectiveness of using models and provides more information on the type of learner most likely to benefit from model texts.