There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Solid-state electrolytes are attracting increasing interest for electrochemical energy storage technologies. In this Review, we provide a background overview and discuss the state of the art, ion-transport mechanisms and fundamental properties of solid-state electrolyte materials of interest for energy storage applications. We focus on recent advances in various classes of battery chemistries and systems that are enabled by solid electrolytes, including all-solid-state lithium-ion batteries and emerging solid-electrolyte lithium batteries that feature cathodes with liquid or gaseous active materials (for example, lithium–air, lithium–sulfur and lithium–bromine systems). A low-cost, safe, aqueous electrochemical energy storage concept with a ‘mediator-ion’ solid electrolyte is also discussed. Advanced battery systems based on solid electrolytes would revitalize the rechargeable battery field because of their safety, excellent stability, long cycle lives and low cost. However, great effort will be needed to implement solid-electrolyte batteries as viable energy storage systems. In this context, we discuss the main issues that must be addressed, such as achieving acceptable ionic conductivity, electrochemical stability and mechanical properties of the solid electrolytes, as well as a compatible electrolyte/electrode interface. This Review details recent advances in battery chemistries and systems enabled by solid electrolytes, including all-solid-state lithium-ion, lithium–air, lithium–sulfur and lithium–bromine batteries, as well as an aqueous battery concept with a mediator-ion solid electrolyte.

Lithium battery chemistries enabled by solid-state electrolytes

The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

羟氨苄青霉素引起大疱性类天疱疮样疹

Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

Complex Hydrides for Hydrogen Storage

In this work, we reported the thin barrier InGaN channel double-heterostructure high electron mobility transistor (DH-HEMT) for millimeter wave power amplifier (PA) application for the first time. The fabricated device achieved high DC and RF characteristics, including the off-state leakage current as low as 2.6×10-8 A/mm, the large ION/IOFF current ratio of 108, and the on-resistance of 2.7 Ω•mm. The saturation current collapse ratio (CCR) of the device is only 5.8% under the double pulse test. The peak current-off frequency (fT) and maximum oscillation frequency (fmax) of the device are 50 and 131 GHz, respectively. At the large-signal power response in the millimeter wave band, the saturation output power density of the device is 1.5 W/mm, and the linear gain reaches 10 dB. This work shows great potential for the thin barrier InGaN channel DH-HEMT applied for high-performance millimeter wave PA applications.

High-performance Thin-barrier InGaN Channel DH-HEMT for Millimeter Wave Applications

With the rapid progress of artificial intelligence, various perception networks were constructed to enable Internet of Things (IoT) applications, thereby imposing formidable challenges to communication bandwidth and information security. Memristors, which exhibit powerful analog computing capabilities, emerged as a promising solution expected to address these challenges by enabling the development of the next-generation high-speed digital compressed sensing (CS) technologies for edge computing. However, the mechanisms and fundamental properties of memristors for achieving CS remain unclear, and the underlying principles for selecting different implementation methods based on various application scenarios have yet to be elucidated. A comprehensive overview of memristor-based CS techniques is currently lacking. In this article, we systematically presented CS requirements on device performance and hardware implementation. The relevant models were analyzed and discussed from the mechanism level to elaborate the memristor CS system scientifically. In addition, the method of deploying CS hardware using the powerful signal processing capabilities and unique performance of memristors was further reviewed. Subsequently, the potential of memristors in all-in-one compression and encryption was anticipated. Finally, existing challenges and future outlooks for memristor-based CS systems were discussed.

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Memristor-Based Signal Processing for Compressed Sensing

Negative bias-induced threshold voltage instability and zener/interface trapping mechanism in GaN-based MIS-HEMTs

The current transport mechanisms of Ni/Au/Ni schottky contact in AlGaN/GaN high electron mobility transistors are investigated from room temperature to 473 K combined experiments and numerical simulations. The ideality factor extracted by the forward schottky characteristics is temperature sensitive and far from the value which the ideal contact should has. To have a deep understanding of the real transport behavior, both the experimental results in room temperature and 473 K are fitted by the four transport mechanisms possible in the schottky contact using numerical simulations with the schottky series resistance involved. And it can be found that the thermionic emission current portion increases at high temperature, while the dominant mechanism is still the tunneling current assisted by dislocations both at room temperature and 473 K.

Analysis of Schottky Forward Current Transport Mechanisms in AlGaN /GaN HEMTs over a Wide Temperature Range

The major components of the dye-sensitized solar cell (DSSC) consist of a dye, a semiconductor electrode, an electrolyte layer, as well as a counter electrode layer

Xiaohua Ma

Papers

High-performance Thin-barrier InGaN Channel DH-HEMT for Millimeter Wave Applications

Memristor-Based Signal Processing for Compressed Sensing

Negative bias-induced threshold voltage instability and zener/interface trapping mechanism in GaN-based MIS-HEMTs

Analysis of Schottky Forward Current Transport Mechanisms in AlGaN /GaN HEMTs over a Wide Temperature Range

Dye-Sensitized Solar Cell