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To realize the practical application of lithium-sulfur (Li-S) batteries, there is a need to inhibit uncontrolled Li deposition by facilitating Li-ion migration, and suppress the irreversible consumption of cathodes by preventing polysulfide shuttling. However, a permselective artifical membrane or interlayer which features fast ion transport but low polysulfide crossover is elusive. Here, we report the design and synthesis of a fluorinated covalent organic framework (4F-COF)-based membrane with a high permselectivity and increased battery lifespan. Combining density functional theory calculation, molecular dynamic simulation, and in situ Raman analysis, we demonstrate that fluorinated COF eliminates polysulfides shutting and dendritic lithium formation. Consequently, Li symmetrical cells demonstrate Li plating/stripping behaviors for 2000 h under 1 mA cm −2 . More importantly, Li−S batteries based on the 4F-COF/PP separator achieve cycling retention of 82.3% over 1000 cycles at 2 C, rate performance of 568.0 mA h g −1 at 10 C, and an areal capacity of 7.60 mA h cm −2 with a high sulfur loading (∼9 mg cm −2 ). This work demonstrates that functionalizing nanochannels in COFs can impart permselectivity for energy storage applications.

The forming of adsorbent powder is the bottleneck of the current technology for lithium adsorption from brine. In this study, an epoxy resin (E-12) was directly adopted to prepare a cylindrical granular adsorbent (the EP/HMO composite) with excellent adsorption performance. Furthermore, the conventional adsorption–desorption process was optimized to improve the adsorptive efficiency for lithium. The batch experimental results showed that the adsorptive capacity for lithium per gram of granular adsorbents was 30.2 mg g–1, disclosing the highest uptake of lithium reported in the literature to our knowledge. The continuous adsorption–desorption experimental results presented that the adsorptive capacities for lithium in LiCl solution and sampled brine were 21.3 mg g–1 HMO and 17.2 mg g–1 HMO, respectively. Moreover, 30 cyclic adsorption–desorption experiments were carried out under optimized operating conditions. The lithium recovery rate of the optimized method was 2.34 times higher than that of the conventional method, which was beneficial for the industrial application of adsorption with a packed column.

Simultaneously attaining high gravimetric energy density (E g ) and volumetric energy density (E v ) in lithium-sulfur (Li-S) batteries is a longstanding challenge that has to be solved for practical application, which demands breakthroughs in electrode materials with optimized functionality and structure. Herein, anthraquinone-containing, reactive-type polymer tubes (PQT) that can be used to regulate the redox chemistry of sulfur species are designed and prepared for practical Li-S batteries. PQT favors a similar redox potential window as sulfur, which effectively facilitates the immobilization and conversion of sulfur species through a reversible lithiation/delithiation process. Its tubular structure and high tap density is vital to the fabrication of intact electrode with high sulfur loading and minimizing electrolyte intake during battery operation. With all these contributions, Li-S battery with PQT/S cathode exhibits a stable cycling capacity (73% at 2.0 C over 1000 cycles), remarkable rate performance (514.2 mAh g −1 at 10 C), and a high areal capacity of 7.20 mAh g −1 with high sulfur loading under lean electrolyte condition. More importantly, the assembled Li-S pouch cell delivers an E g of 329 Wh kg −1 and an E v of 401 Wh L −1 , which meets the requirement for practical operation.

Undergraduate electrical engineering students often fail to see the real life relevance of concepts taught in traditional lectures and classroom instruction. Our research shows how this problem can be addressed. This paper describes the process of developing an Extended Specialty Course Education (ESCE) project for teaching over-voltage courses to junior undergraduates at Wuhan University. This project included two pedagogical components: literature review skills and project-based learning (PBL). First, students are asked to search text-based literatures from electronic databases and analyze the latest over-voltage research results; secondly, students design a project using specialty software in teams to demonstrate core over-voltage concepts. Students' feedback and a comparison of final exam scores suggest that PBL helps students become more engaged with coursework, improves the cohort's average final scores and hopefully hones the participants' critical thinking skills. Since open-ended general comments from participants supported this instructional method, extended educational techniques will be more widely applied in future courses. Several convincing ideas for improving specialized engineering education will be presented after discussing this project. KeywordsExtended specialized course education (ESCE), project-based learning (PBL), assessment, demonstration, feedback Engineering education should help students understand the discipline as an applied science profession so as to encourage them to acquire the knowledge and skills