Lithium–sulfur batteries are a promising energy-storage technology due to their relatively low cost and high theoretical energy density. However, one of their major technical problems is the shuttling of soluble polysulfides between electrodes, resulting in rapid capacity fading. Here, we present a metal–organic framework (MOF)-based battery separator to mitigate the shuttling problem. We show that the MOF-based separator acts as an ionic sieve in lithium–sulfur batteries, which selectively sieves Li+ ions while e ciently suppressing undesired polysulfides migrating to the anode side. When a sulfur-containing mesoporous carbon material (approximately 70 wt% sulfur content) is used as a cathode composite without elaborate synthesis or surface modification, a lithium–sulfur battery with a MOF-based separator exhibits a low capacity decay rate (0.019% per cycle over 1,500 cycles). Moreover, there is almost no capacity fading after the initial 100 cycles. Our approach demonstrates the potential for MOF-based materials as separators for energy-storage applications.
上传时间： 2017-11-23
上传用户：653357637
Wireless penetration has witnessed explosive growth over the last two decades. Accordingly, wireless devices have become much denser per unit area, resulting in an overcrowded usage of wireless resources. To avoid radio interferences and packet collisions, wireless stations have to exchange control messages to coordinate well. The existing wisdoms of conveying control messages could be classified into three categories: explicit, implicit, or hybrid.
标签： Transmission Attachment Networks Wireless in
上传时间： 2020-05-26
上传用户：shancjb
The growing interest for high data rate wireless communications over the last few decades gave rise to the emergence of a number of wideband wireless systems. The resulting scarcity of frequency spectrum has been forcing wireless system designers to develop methods that will push the spectral efficiency to its limit.
标签： Algorithms Baseband Receiver
上传时间： 2020-05-26
上传用户：shancjb
In order to improve the spectral efficiency in wireless communications, multiple antennas are employed at both transmitter and receiver sides, where the resulting system is referred to as the multiple-input multiple-output (MIMO) system. In MIMO systems, it is usually requiredto detect signals jointly as multiple signals are transmitted through multiple signal paths between the transmitter and the receiver. This joint detection becomes the MIMO detection.
标签： Complexity Detection MIMO Low
上传时间： 2020-05-27
上传用户：shancjb
Wireless communications has become a field of enormous scientific and economic interest. Recent success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically assume that the radio channel remains constant for the duration of a data block. However, researchers and system designers are increasingly shifting their attention to channels that may vary within a block. In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as being “doubly dispersive.”
标签： Time-Varying Channels
上传时间： 2020-06-01
上传用户：shancjb
Battery systems for energy storage are among the most relevant technologies of the 21 st century. They – in particular modern lithium-ion batteries (LIB) – are enablers for the market success of electric vehicles (EV) as well as for stationary energy storage solutions for balancing fluctuations in electricity grids resulting from the integrationofrenewableenergysourceswithvolatilesupply 1 .BothEVandstationary storage solutions are important because they foster the transition from the usage of fossil energy carriers towards cleaner renewable energy sources. Furthermore, EV cause less local air pollution and noise emissions compared to conventional combustion engine vehicles resulting in better air quality especially in urban areas. Unfortunately, to this day, various technological and economic challenges impede a broad application of batteries for EV as well as for large scale energy storage and load leveling in electricity grids.
标签： Multiscale Simulation Approach
上传时间： 2020-06-06
上传用户：shancjb
Design for manufacturability and statistical design encompass a number of activities and areas of study spanning the integrated circuit design and manufacturing worlds. In the early days of the planar integrated circuit, it was typical for a handful of practitioners working on a particular design to have a fairly complete understanding of the manufacturing process, the resulting semiconductor active and passive devices, as well as the resulting circuit - often composed of as few as tens of devices. With the success of semiconductor scaling, predicted and - to a certain extent even driven - by Moore’s law, and the vastly increased complexity of modern nano-meter scale processes and the billion-device circuits they allow, there came a necessary separation between the various disciplines.
标签： Manufacturability Statistical Design for and
上传时间： 2020-06-10
上传用户：shancjb
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上传时间： 2022-06-25
上传用户：moh2000
