다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Due to their high energy density and low material cost, lithium–sulfur batteries represent a promising energy storage system for a multitude of emerging applications, ranging from stationary grid storage to mobile electric vehicles. This review aims to summarize major developments in the field of lithium–sulfur batteries, starting from an overview of their electrochemistry, technical challenges and potential solutions, along with some theoretical calculation results to advance our understanding of the material interactions involved. Next, we examine the most extensively-used design strategy: encapsulation of sulfur cathodes in carbon host materials. Other emerging host materials, such as polymeric and inorganic materials, are discussed as well. This is followed by a survey of novel battery configurations, including the use of lithium sulfide cathodes and lithium polysulfide catholytes, as well as recent burgeoning efforts in the modification of separators and protection of lithium metal anodes. Finally, we conclude with an outlook section to offer some insight on the future directions and prospects of lithium–sulfur batteries.

Designing high-energy lithium–sulfur batteries

Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption

Fiber‐Based Wearable Electronics: A Review of Materials, Fabrication, Devices, and Applications

Amid burgeoning environmental concerns, electrochemical energy storage has rapidly gained momentum. Among the contenders in the ‘beyond lithium’ energy storage arena, the lithium–sulfur (Li–S) battery has emerged as particularly promising, owing to its potential to reversibly store considerable electrical energy at low cost. Whether or not Li–S energy storage will be able to fulfil this potential depends on simultaneously solving many aspects of its underlying conversion chemistry. Here, we review recent developments in tackling the dissolution of polysulfides — a fundamental problem in Li–S batteries — focusing on both experimental and computational approaches to tailor the chemical interactions between the sulfur host materials and polysulfides. We also discuss smart cathode architectures enabled by recent materials engineering, especially for high areal sulfur loading, as well as innovative electrolyte design to control the solubility of polysulfides. Key factors that allow long-life and high-loading Li–S batteries are summarized. Li–S batteries are a low-cost and high-energy storage system but their full potential is yet to be realized. This Review surveys recent advances in understanding polysulfide chemistry at the positive electrode and the electrolyte and discusses approaches towards long-life and high-loading batteries.

Advances in lithium-sulfur batteries based on multifunctional cathodes and electrolytes

The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated. Simply via physical compression, the microwave absorption performance can be tuned. The qualified bandwidth coverage of 93.8% (60.5 GHz/64.5 GHz) is achieved for the GF under 90% compressive strain (1.0 mm thickness). This mainly because of the 3D conductive network.

Broadband and Tunable High‐Performance Microwave Absorption of an Ultralight and Highly Compressible Graphene Foam

Aligned carbon-nanotube (CNT) sheets are used as building blocks to prepare light-weight, frequency-tunable and high-performance microwave absorbers, and the absorption frequency can be accurately controlled by stacking them with different intersectional angles. A remarkable reflection loss of -47.66 dB is achieved by stacking four aligned CNT sheets with an intersectional angle of 90° between two neighboring ones. The incorporation of a second phase such as a metal and a conducting polymer greatly enhances the microwave-absorption capability.

Cross-Stacking Aligned Carbon-Nanotube Films to Tune Microwave Absorption Frequencies and Increase Absorption Intensities

Flexible and portable devices are a mainstream direction in modern electronics and related multidisciplinary fields. To this end, they are generally required to be stretchable to satisfy various substrates. As a result, stretchable devices, such as electrochemical supercapacitors, lithium-ion batteries, organic solar cells, organic light-emitting diodes, field-effect transistors, and artificial skin sensors have been widely studied. However, these stretchable devices are made in a conventional planar format that has largely hindered their development. For the portable applications, the devices need to be lightweight and small, though it is difficult for them to be made into efficient microdevices. In particular, it is challenging or even impossible for them to be used in electronic circuits and textiles that are urgently required also in a wide variety of other fields, such as microelectronic applications. Recently, some attempts have been made to fabricate wire-shaped microdevices, such as electrochemical supercapacitors. They have been generally produced by twisting two fiber electrodes with electrolytes coated on the surface. Several examples have been also successfully shown to make fiber-shaped supercapacitors with a coaxial structure. Compared with their planar counterparts, the wire or fiber shape enables promising advantages such as being lightweight and woven into textiles. Although the wire and fiber-shaped supercapacitors are also flexible with high electrochemical performance, they are not stretchable, which is critically important for many applications. For instance, the resulting electronic textiles could easily break during the use if they were not stretchable. To the best of our knowledge, herein we have, for the first time, developed a novel family of highly stretchable, fibershaped high-performance supercapacitors. Aligned carbon nanotube (CNT) sheets that are sequentially wrapped on an elastic fiber serve as two electrodes. The use of aligned CNT sheets offers combined remarkable properties including high flexibility, tensile strength, electrical conductivity, and mechanical and thermal stability. As a result, the fibershaped supercapacitor maintains a high specific capacitance of approximately 18 F/g after stretch by 75% for 100 cycles. Spinnable CNT arrays were first synthesized by chemical vapor deposition. A scanning electron microscopy (SEM) image of the array with height of 230 mm is shown in the Supporting Information, Figure S1, and the CNT shows a multi-walled structure with diameter of about 10 nm (Supporting Information, Figure S2). Aligned CNT sheets could be then continuously drawn from the array and easily attached to various substrates. Elastic fibers were used herein to offer the stretchability in the resulting supercapactiors, and rubber fibers have been mainly studied as a demonstration. For a typical fabrication on the fiber-shaped supercapacitor (Figure 1), a rubber fiber was first coated with a thin layer of

A Highly Stretchable, Fiber-Shaped Supercapacitor

Sensitivity is a crucial parameter for flexible pressure sensors and electronic skins. While introducing microstructures (e.g., micro-pyramids) can effectively improve the sensitivity, it in turn leads to a limited pressure-response range due to the poor structural compressibility. Here, we report a strategy of engineering intrafillable microstructures that can significantly boost the sensitivity while simultaneously broadening the pressure responding range. Such intrafillable microstructures feature undercuts and grooves that accommodate deformed surface microstructures, effectively enhancing the structural compressibility and the pressure-response range. The intrafillable iontronic sensor exhibits an unprecedentedly high sensitivity (Smin > 220 kPa−1) over a broad pressure regime (0.08 Pa-360 kPa), and an ultrahigh pressure resolution (18 Pa or 0.0056%) over the full pressure range, together with remarkable mechanical stability. The intrafillable structure is a general design expected to be applied to other types of sensors to achieve a broader pressure-response range and a higher sensitivity. Though flexible pressure sensors are attractive for next-generation applications, limitations in its performance hinder widespread adoption. Here, the authors report an iontronic flexible pressure sensor with graded intrafillable architecture that shows high sensitivity over a broad pressure range.

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Graded intrafillable architecture-based iontronic pressure sensor with ultra-broad-range high sensitivity

Twisted, aligned carbon nanotube/silicon composite fibers with remarkable mechanical and electronic properties are designed to develop novel flexible lithium-ion batteries with a high cyclic stability. The core-sheath architecture and the aligned structure of the composite nanotube offer excellent combined properties.

Twisted Aligned Carbon Nanotube/Silicon Composite Fiber Anode for Flexible Wire‐Shaped Lithium‐Ion Battery

Novel nanostructured composite fibers based on graphene and carbon nanotubes are developed with high tensile strength, electrical conductivity, and electrocatalytic activity. As two application demonstrations, these composite fibers are used to fabricate flexible, wire-shaped dye-sensitized solar cells and electrochemical supercapacitors, both with high performances, for example, a maximal energy conversion efficiency of 8.50% and a specific capacitance of ca. 31.50 F g(-1). These miniature wire-shaped devices are further shown to be promising for flexible and portable electronic facilities.

Jue Deng

Papers

Cross-Stacking Aligned Carbon-Nanotube Films to Tune Microwave Absorption Frequencies and Increase Absorption Intensities

A Highly Stretchable, Fiber-Shaped Supercapacitor

Graded intrafillable architecture-based iontronic pressure sensor with ultra-broad-range high sensitivity

Twisted Aligned Carbon Nanotube/Silicon Composite Fiber Anode for Flexible Wire‐Shaped Lithium‐Ion Battery

Novel graphene/carbon nanotube composite fibers for efficient wire-shaped miniature energy devices