A Universal Spinning-Coordinating Strategy to Construct Continuous Metal-Nitrogen-Carbon Heterointerface with Boosted Lithium Polysulfides Immobilization for 3D-Printed LiS Batteries.

Constructing intimate coupling between transition metal and carbon nanomaterials is an effective means to achieve strong immobilization of lithium polysulfides (LiPSs) in the applications of lithium-sulfur (LiS) batteries. Herein, a universal spinning-coordinating strategy of constructing continuous metal-nitrogen-carbon (MNC, M = Co, Fe, Ni) heterointerface is reported to covalently bond metal nanoparticles with nitrogen-doped porous carbon fibers (denoted as M/MN@NPCF). Guided by theoretical simulations, the Co/CoN@NPCF hybrid is synthesized as a proof of concept and used as an efficient sulfur host material. The polarized CoNC bridging bonds can induce rapid electron transfer from Co nanoparticles to the NPCF skeleton, promoting the chemical anchoring of LiPSs to improve sulfur utilization. Hence, the as-assembled LiS battery presents a remarkable capacity of 781 mAh g-1 at 2.0 C and a prominent cycling lifespan with a low decay rate of only 0.032% per cycle. Additionally, a well-designed Co/CoN@NPCF-S electrode with a high sulfur loading of 7.1 mg cm-2 is further achieved by 3D printing technique, which demonstrates an excellent areal capacity of 6.4 mAh cm-2 at 0.2 C under a lean-electrolyte condition. The acquired insights into strongly coupled continuous heterointerface in this work pave the way for rational designs of host materials in LiS systems.

Homogeneous electric field and Li+ flux regulation in three-dimensional nanofibrous composite framework for ultra-long-life lithium metal anode.

Lithium (Li) metal is considered as the best anode candidate for next-generation high-energy batteries due to its ultralow electrochemical potential and extremely high theoretical capacity. However, issues arising from the undesired growth of lithium dendrites and infinite volumetric change have seriously hindered the practical application of lithium metal batteries (LMBs). Here, we designed a super-lithiophilic amorphous zinc oxide-doped carbon nanofiber framework with uniformly-distributed and parallel multichannels (MCCNF@ZnO) to achieve the homogeneous distribution of electric field and Li+ flux. By the assistances of COMSOL Multiphysics simulations and ex-situ scanning electron microscopy, we reveal that the Li metal preferentially deposits into the porous nanochannels inside the nanofibers, followed by its even distribution on the lithiophilic surface of MCCNF@ZnO. Furthermore, the conductive multichannels of the carbon nanofiber skeleton can effectively minimize the partial current density, thereby effectively avoiding the electrochemical polarization and assisting the uniform metallic deposition. As a result, MCCNF@ZnO exhibits a stable CE over 99.2% as the substrate after 500 cycles at the current density of 1 mA cm-2. The symmetrical cell of lithium-loaded MCCNF@ZnO composite electrodes can stably operate over 3300 h at 0.5 mA cm-2, indicating the great potential of MCCNF@ZnO for stabilizing lithium metal anodes in practical applications of LMBs.

Asymmetric Sodiophilic Host Based on a Ag-Modified Carbon Fiber Framework for Dendrite-Free Sodium Metal Anodes.

Sodium (Na) metal is considered a promising anode material for high-energy Na batteries due to its high theoretical capacity and abundant resources. However, uncontrollable dendrite growth during the repeated Na plating/stripping process leads to the issues of low Coulombic efficiency and short circuits, impeding the practical applications of Na metal anodes. Herein, we propose a silver-modified carbon nanofiber (CNF@Ag) host with asymmetric sodiophilic features to effectively improve the deposition behavior of Na metal. Both density functional theory (DFT) calculations and experiment results demonstrate that Na metal can preferentially nucleate on the sodiophilic surface with Ag nanoparticles and uniformly deposit on the whole CNF@Ag host with a "bottom-up growth" mode, thus preventing unsafe dendrite growth at the anode/separator interface. The optimized CNF@Ag framework exhibits an excellent average Coulombic efficiency of 99.9% for 500 cycles during Na plating/stripping at 1 mA cm-2 for 1 mAh cm-2. Moreover, the CNF@Ag-Na symmetric cell displays stable cycling for 500 h with a low voltage hysteresis at 2 mA cm-2. The CNF@Ag-Na//Na3V2(PO4)3 full cell also presents a high reversible specific capacity of 102.7 mAh g-1 for over 200 cycles at 1 C. Therefore, asymmetric sodiophilic engineering presents a facile and efficient approach for developing high-performance Na batteries with high safety and stable cycling performance.

A randomized controlled trial of a nurse-led education pathway for asthmatic children from outpatient to home.

BACKGROUND: Education for asthmatic children in the outpatient department is insufficient. AIM: To evaluate the efficacy of a nurse-led education pathway, a standard education programme, on children with asthma. METHODS: One hundred and eighty participants enrolled and were randomly assigned to either the control group or the intervention group. The intervention group received predetermined step-by-step education sessions based on the self-designed education pathway, while the control group received usual care. Asthma control, health-related quality of life, and health-care utilization measures were taken at baseline and at follow-up visits between February 2016 and May 2018. RESULTS: Significantly higher scores for health-related quality of life and inhaler technique at the third-month visit and asthma control test at the sixth-month visit were seen in the intervention group. The numbers of unscheduled physician visits and school absences were lower in the intervention group than in the control group within 6 months. However, no significant differences were observed in emergency department visits and hospitalizations. CONCLUSION: The nurse-led education pathway could be considered effective for children with asthma visiting the outpatient department.

Predictive accuracy of the Braden Q Scale in risk assessment for paediatric pressure ulcer: A meta-analysis.

AIMS: Paediatric pressure ulcers are a serious problem to healthcare service. Thus, effective and early identification of the risk of developing pressure ulcer is essential. The Braden Q scale is a widely used tool in the risk assessment of paediatric pressure ulcer, but its predictive power is controversial. Hence, we performed a meta-analysis to evaluate the predictive power of the Braden Q scale for pressure ulcer in hospitalised children and offer recommendations for clinical decision. METHODS: Studies that evaluated the predictive power of the Braden Q scale were searched through databases in English and Chinese, including Medline, Cochrane Library, Embase, CINAHL, SinoMed, CNKI, Wangfang and VIP. The studies were screened by two independent reviewers. QUADAS-2 was used to assess the risk of bias of eligible studies. Demographic data and predictive value indices were extracted. The pooled sensitivity, specificity and receiver operating characteristics (ROC) were calculated by MetaDiSc 1.4 using random-effects models. RESULTS: Cochran Q = 26.13 (P = 0.0036) indicated the existence of heterogeneity; the I2 for pooled DOR was 61.7%, suggesting significant heterogeneity among the included studies. The pooled sensitivity and specificity were 0.73 (95% CI: 0.67-0.78) and 0.61 (95% CI: 0. 59-0.63), respectively, yielding a combined DOR of 3.47 (95% CI: 2-6.01). The area under the ROC curve was 0.7078 ± 0.0421, and the overall diagnostic accuracy (Q*) was 0.6591 ± 0.0337. Sensitivity analysis showed the results were robust. CONCLUSION: The Braden Q scale has moderate predictive validity with medium sensitivity and low specificity for pressure ulcers in hospitalised children. Further development and modification of this tool for use in paediatric population are warranted.

Preparation and Electrochemical Properties of Li3V2(PO4)3-xBrx/Carbon Composites as Cathode Materials for Lithium-Ion Batteries.

Li3V2(PO4)3-xBrx/carbon (x = 0.08, 0.14, 0.20, and 0.26) composites as cathode materials for lithium-ion batteries were prepared through partially substituting PO43- with Br-, via a rheological phase reaction method. The crystal structure and morphology of the as-prepared composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and electrochemical properties were evaluated by charge/discharge cycling and electrochemical impedance spectroscopy (EIS). XRD results reveal that the Li3V2(PO4)3-xBrx/carbon composites with solid solution phase are well crystallized and have the same monoclinic structure as the pristine Li3V2(PO4)3/carbon composite. It is indicated by SEM images that the Li3V2(PO4)3-xBrx/carbon composites possess large and irregular particles, with an increasing Br- content. Among the Li3V2(PO4)3-xBrx/carbon composites, the Li3V2(PO4)2.86Br0.14/carbon composite shows the highest initial discharge capacity of 178.33 mAh·g-1 at the current rate of 30 mA·g-1 in the voltage range of 4.8-3.0 V, and the discharge capacity of 139.66 mAh·g-1 remains after 100 charge/discharge cycles. Even if operated at the current rate of 90 mA·g-1, Li3V2(PO4)2.86Br0.14/carbon composite still releases the initial discharge capacity of 156.57 mAh·g-1, and the discharge capacity of 123.3 mAh·g-1 can be maintained after the same number of cycles, which is beyond the discharge capacity and cycleability of the pristine Li3V2(PO4)3/carbon composite. EIS results imply that the Li3V2(PO4)2.86Br0.14/carbon composite demonstrates a decreased charge transfer resistance and preserves a good interfacial compatibility between solid electrode and electrolyte solution, compared with the pristine Li3V2(PO4)3/carbon composite upon cycling.