Structural Engineering of Hierarchical Micro‐nanostructured Ge-C Framework by Controlling the Nucleation for Ultralong Life Li Storage

The rational design of a proper electrode structure with high energy and power densities, long cycling lifespan, and low cost still remains a significant challenge for developing advanced energy storage systems. Germanium is a highly promising anode material for high-performance lithium ion batteries due to its large specific capacity and remarkable rate capability. Nevertheless, poor cycling stability and high price significantly limit its practical application. Herein, a facile and scalable structural engineering strategy is proposed by controlling the nucleation to fabricate a unique hierarchical micro-nanostructured Ge-C framework, featuring high tap density, reduced Ge content, superb structural stability, and a 3D conductive network. The constructed architecture has demonstrated outstanding reversible capacity of 1541.1 mA h g −1 after 3000 cycles at 1000 mA g −1 (with 99.6% capacity retention), markedly exceeding all the reported Ge-C electrodes regarding long cycling stability. Notably, the assembled full cell exhibits superior performance as well. The work paves the way to constructing novel metal-carbon materials with high performance and low cost for energy-related applications

Evapotranspiration estimation considering anthropogenic heat based on remote sensing in urban area

Urbanization influences hydrologic cycle significantly on local, regional even global scale. With urbanization the water resources demand for dense population sharpened, thus it is a great challenge to ensure water supply for some metropolises such as Beijing. Urban area is traditionally considered as the area with lower evapotranspiration (ET) on account of the impervious surface and the lower wind speed. For most remote sensing models, the ET, defined as latent heat in energy budget, is estimated as the difference between net radiation and sensible heat. The sensible heat is generally higher in urban area due to the high surface temperature caused by heat island, therefore the latent heat (i.e. the ET) in urban area is lower than that in other region. We estimated water consumption from 2003 to 2012 in Beijing based on water balance method and found that the annual mean ET in urban area was about 654 mm. However, using Surface Energy Balance System (SEBS) model, the annual mean ET in urban area was only 348 mm. We attributed this inconsistence to the impact of anthropogenic heat and quantified this impact on the basis of the night-light maps. Therefore, a new model SEBS-Urban, coupling SEBS model and anthropogenic heat was developed to estimate the ET in urban area. The ET in urban area of Beijing estimated by SEBS-Urban showed a good agreement with the ET from water balance method. The findings from this study highlighted that anthropogenic heat should be included in the surface energy budget for a highly urbanized area

Arthroscopic debridement of anterior ankle impingement in patients with chronic lateral ankle instability

Abstract Background The aim of this study was to determine the functional and radiological outcomes of arthroscopic treatment of anterior ankle impingement (AAI) in patients with chronic lateral ankle instability (CAI). Methods All patients with CAI between June 2012 and May 2015 were invited to participate in this investigation. All of them accepted open modified Broström repair of lateral ankle ligaments and were divided into two groups: AAI group (with anterior ankle impingement) and pure CAI group (without anterior ankle impingement). All of them were followed up using American Orthopaedic Foot and Ankle Society Score (AOFAS), Karlsson Ankle Functional Score and Tegner activity score. Ankle dorsiflexion was also examined. X-ray examination was applied to investigate anterior tibiotalar osteophytes. Results Finally, a total of 60 patients were followed up at a mean of 37 ± 10 months, including 22 patients in the AAI group and 38 patients in the pure CAI group. Preoperatively, the AAI group had significant lower AOFAS score (62.9 ± 11.7 vs 72.9 ± 11.1; p = 0.002) and Tegner activity score (1.5 ± 0.8 vs 2.1 ± 1.0; p = 0.04) respectively when compared with the pure CAI group. The ankle dorsiflexion of the AAI group (13 ± 2.1) was also significantly lower than that of the pure CAI group (26.2 ± 2.1) (p = 0.001). However, there was no significant difference in the AOFAS score or the Karlsson score or the Tegner score or the Ankle dorsiflexion between the two groups postoperatively. The postoperative X-ray images demonstrated complete osteophyte resection in all patients, and no recurrence of osteophyte. Conclusion The functional outcome scores and dorsiflexion had significantly improved postoperatively. Combined treatment of chronic ankle instability and anterior ankle impingement produced satisfactory surgical outcomes in patients with CAI accompanied by anterior ankle impingement symptom

Simultaneously Enhancing the Flame Retardancy, Water Resistance, and Mechanical Properties of Flame-Retardant Polypropylene via a Linear Vinyl Polysiloxane-Coated Ammonium Polyphosphate

It is challenging to improve the water resistance, flame retardancy, mechanical performance, and balance of halogen-free flame-retardant polypropylene (PP) composites. For this purpose, a linear vinyl polysiloxane (PD) was synthesized and then self-crosslinked under benzoyl peroxide to prepare surface-coated ammonium polyphosphate (APP@PD). Apparently, this linear vinyl polysiloxane self-crosslinking coating strategy was completely different from the commonly used sol-gel-coated APP with silane monomers. After coating, the water contact angles (WCA) of APP and APP@PD were 26.8° and 111.7°, respectively, showing high hydrophobicity. More importantly, PP/APP@PD/dipentaerythritol (DPER) showed a higher limiting oxygen index (LOI) and better UL-94 V-0 rate in comparison with PP/APP/DPER composites. After water immersion at 70 °C for 168 h, only PP/APP@PD/DPER kept the UL-94 V-0 rate and lowered the deterioration of the LOI, reflecting the better water-resistance property of APP@PD. Consistently, the cone calorimeter test results displayed a 26.2% and 16.7% reduction in peak heat release rate (PHRR) and total smoke production (TSP), respectively. Meanwhile, the time to peak smoke production rate (TPSPR) increased by 90.2%. The interfacial free energy (IFE) between APP@PD and PP was calculated to evaluate the interfacial interaction between PP and APP@PD. A reduction of 84.2% in the IFE between APP@PD and PP is responsible for the improvement in compatibility and the increase in flame retardancy, water resistance, and mechanical properties of the composites

Structural Engineering of Hierarchical Micro‐nanostructured Ge-C Framework by Controlling the Nucleation for Ultralong Life Li Storage

The rational design of a proper electrode structure with high energy and power densities, long cycling lifespan, and low cost still remains a significant challenge for developing advanced energy storage systems. Germanium is a highly promising anode material for high-performance lithium ion batteries due to its large specific capacity and remarkable rate capability. Nevertheless, poor cycling stability and high price significantly limit its practical application. Herein, a facile and scalable structural engineering strategy is proposed by controlling the nucleation to fabricate a unique hierarchical micro-nanostructured Ge-C framework, featuring high tap density, reduced Ge content, superb structural stability, and a 3D conductive network. The constructed architecture has demonstrated outstanding reversible capacity of 1541.1 mA h g −1 after 3000 cycles at 1000 mA g −1 (with 99.6% capacity retention), markedly exceeding all the reported Ge-C electrodes regarding long cycling stability. Notably, the assembled full cell exhibits superior performance as well. The work paves the way to constructing novel metal-carbon materials with high performance and low cost for energy-related applications

Recent progress on alloy-based anode materials for potassium-ion batteries

Potassium-ion batteries (PIBs) are considered as promising alternatives to lithium-ion batteries due to the abundant potassium resources in the Earth’s crust. Establishing high-performance anode materials for PIBs is essential to the development of PIBs. Recently, significant research effort has been devoted to developing novel anode materials for PIBs. Alloy-based anode materials that undergo alloying reactions and feature combined conversion and alloying reactions are attractive candidates due to their high theoretical capacities. In this review, the current understanding of the mechanisms of alloy-based anode materials for PIBs is presented. The modification strategies and recent research progress of alloy-based anodes and their composites for potassium storage are summarized and discussed. The corresponding challenges and future perspectives of these materials are also proposed

Constructing Layered Nanostructures from Non-Layered Sulfide Crystals via Surface Charge Manipulation Strategy

2D non-layered metal sulfides possess intriguing properties, rendering them bright application prospects in energy storage and conversion, however, the synthesis of non-layered metal sulfide nanosheets is still significantly challenging. Herein, a surface-charge-regulating strategy is developed to fabricate microsized 2D non-layered metal sulfides via manipulation of the isoelectric point, which can easily modulate the manner of surface charge arrangement during the growth of crystal nuclei. The result of this strategy are materials that are completely assembled with a preferred orientation but comprise a large lateral size with maintaining atomic thickness. A series of modified sulfides are successfully synthesized, demonstrating that their microarchitectures are shifted in an expected manner. Then, one of these materials, In4SnS8, approaches a promising candidate for sodium storage by means of its structural integrity, boosted transfer kinetics, and abundant active sites. The proposed synthetic protocol can open up a new opportunity to explore 2D non-layered materials for energy-related applications

Boosting Na-O2 battery performance by regulating the morphology of NaO2

Na-O2 batteries, as one of the most promising advanced battery technologies, have attracted attention due to their low cost and high energy density. The formation mechanism of discharge products in Na-O2 batteries directly relates to their electrochemical performance, yet our understanding of it is still meagre. In this work, the growth pattern of NaO2 is investigated by in-situ X-ray diffraction and the morphologies of discharge products have been linked to their corresponding electrochemical performance. Furthermore, the ratio between the rates of solvation and desolvation is proposed for the first time as a descriptor (denoted as α) for predicting the morphological variation of NaO2 by tuning the ratio of 1, 2-dimethoxyethane (DME): tetraethylene glycol dimethyl ether (TEGDME) in electrolyte (from 0:5 to 5:0). As a result, combined with the optimized electrolyte (DME: TEGDME of 4:1) and an efficient cathode (N-doped porous carbon), easy-to-decompose thick sheet-like NaO2 could be produced during discharge, achieving highly efficient Na-O2 batteries performance (excellent rate capability, high discharge capacity of 5812 mAh g−1, the highest reported Coulombic efficiency of 91.1%, and superior cycling performance over 100 cycles at a current density of 1000 mA g−1). This work provides new insight into the growth patterns of discharge products and paves the way to a deeper understanding of the reaction mechanism as well as improving battery performance