Lithium−sulfur (Li−S) batteries suffer from multiple complex and often interwoven issues, such as the low electronic conductivity of sulfur and Li 2 S/Li 2 S 2 , shuttle effect, and sluggish electrochemical kinetics of lithium polysulfides (LiPSs). Guided by theoretical calculations, a multifunctional catalyst of isolated single-atom nickel in an optimal Ni−N 5 active moiety incorporated in hollow nitrogen-doped porous carbon (Ni−N 5 /HNPC) is constructed and acts as an ideal host for a sulfur cathode. The host improved electrical conductivity, enhanced physical-chemical dual restricting capability toward LiPSs, and, more importantly, boosted the redox reaction kinetics by the Ni−N 5 active moiety. Therefore, the Ni−N 5 /HNPC/S cathode exhibits superior rate performance, long-term cycling stability, and good areal capacity at high sulfur loading. This work highlights the important role of the coordination number of active centers in single-atom catalysts and provides a strategy to design a hollow nanoarchitecture with single-atom active sites for high-performance Li−S batteries.

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Background and Aim: To compare the efficacy and safety of esophagogastroduodenoscopy (EGD)-colonoscopy and colonoscopy-EGD sequences for patients subjected to same-day bidirectional endoscopy under remifentanil and propofol sedation.Methods: A total of 209 eligible outpatients scheduled for diagnostic same-day bidirectional endoscopy between 16 February 2016 and 30 April 2016 were randomly assigned to the EGDcolonoscopy (n = 106) and colonoscopy-EGD (n = 103) sequence groups. Primary endpoint was total dose of propofol required for the procedure. Secondary endpoints included duration of endoscopy, patient satisfaction, adverse effects, endoscopy findings, and cardiopulmonary responses of the patients.Results: Patients in the two groups were similar in terms of demographic and clinical data (P > 0.05). EGD-colonoscopy sequence group had lesser requirement of propofol for sedation (P < 0.05), faster recovery (P < 0.001), and lesser influence on mean arterial pressure (MAP) during the endoscopy (P < 0.05). Duration of EGD and colonoscopy, patient satisfaction, adverse effects, and pathological findings did not differ between the two groups. Conclusions:The EGD-colonoscopy sequence may be considered the preferred sequence for same-day bidirectional endoscopy as a result of less cardiovascular stress, lessened need for sedation with propofol, and faster recovery.

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is one of the most promising candidate solid electrolytes for high-safety solid-state batteries. However, similar to other solid electrolytes containing volatile components during high-temperature sintering, the preparation of densified LLZO with high conductivity is challenging involving the complicated gas−liquid−solid sintering mechanism. Further attention on establishing low-cost laborastory-scale preparation craft platform of LLZO ceramic is also required. This work demonstrates a "pellet on gravel" sintering strategy, which is performed in a MgO crucible and box furnace under ambient air without any special equipment or expensive consumables. In addition, the competition between lithium loss from the sintering system and internal grain densification is critically studied, whereas the influences of particle surface energy, Li-loss amount, and initial excess Li 2 O amount are uncovered. Based on the sintering behavior and mechanism, optimized craft platform for preparing dense LLZO solid electrolytes including mixing, calcination, particle tailoring and sintering is provided. Finally, exemplary Ta-doped LLZO pellets with 2 wt % La 2 Zr 2 O 7 additives sintered at 1260−1320 °C for 20 min deliver Li + conductivities of ∼9 × 10 −4 S cm −1 at 25 °C, relative densities of >96%, and a dense cross-sectional microstructure. As a practical demonstration, LLZO solid electrolyte with optimized performance is applied in both Li−Li symmetric cells and Li−S batteries. This work sheds light on the practical production of high-quality LLZO ceramics and provides inspiration for sintering ceramics containing volatile compounds.

Lithium–sulfur (Li–S) batteries have attracted considerable attention over the last two decades because of a high energy density and low cost. However, the wide application of Li–S batteries has been severely impeded due to the poor electrical conductivity of S, shuttling effect of soluble lithium polysulfides (LiPSs), and sluggish redox kinetics of S species, especially under high S loading. To address all these issues, a Ni–CeO2 heterostructure‐doped carbon nanofiber (Ni‐CeO2‐CNF) is developed as an S host that combines the strong adsorption with the high catalytic activity and the good electrical conductivity, where the LiPSs anchored on the heterostructure surface can directly gain electrons from the current collector and realize a fast conversion between S8 and Li2S. Therefore, Li–S batteries with S@Ni‐CeO2‐CNF cathodes exhibit superior long‐term cycling stability, with a capacity decay of 0.046% per cycle over 1000 cycles, even at 2 C. Noteworthy, under a sulfur loading up to 6 mg cm−2, a high reversible areal capacity of 5.3 mAh cm−2 can be achieved after 50 cycles at 0.1 C. The heterostructure‐modified S cathode effectively reconciles the thermodynamic and kinetic characteristics of LiPSs for adsorption and conversion, furthering the development of high‐performance Li–S batteries.

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