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

This article presents a broadband amplifier for high-speed modulators and measurement driver circuits using distributed amplifiers (DAs) configuration. The flat low-frequency performance of the conventional DAs is limited by termination impedance. This article shows that on- chip low-frequency extension can be achieved by optimizing the capacitively coupled circuit and impedance termination. Although capacitively coupled circuit has been introduced in previous studies to extend the high-frequency gain, sufficient analysis has not been studied. Furthermore, a novel broadband equalizer termination applying for distributed configuration is introduced, which can be employed to balance the rising gain. This DA features the lowest cutoff frequency among broadband amplifiers using the on- chip circuit. The amplifier provides a comparable low-frequency performance of megahertz (MHz) with greater than 15-dB gain and benchmarks the first demonstration of a flat MHz performance monolithic microwave integrated circuit (MMIC) using on- chip passive components. The proposed amplifier achieves a 17-dBm output 1-dB compression point (OP1dB) covering eight-octave bandwidth verified using a 0.15- $\mu \text{m}$ GaAs pseudomorphic high-electron-mobility transistor (pHEMT) technology. The new design architecture combined with the broadband equalizer characteristics and gate series network can provide performance benefits for optic modulators, instrumentations, and advanced broadband transmitters.

A Broadband Amplifier With Flat Bandwidth for Modulator and Measurement Driver Circuits

We present a detailed analysis of the trap states in atomic layer deposition Al2O3/InAlN/GaN high electron mobility transistors grown by pulsed metal organic chemical vapor deposition. Trap densities, trap energies and time constants are determined by frequency-dependent conductance measurements. A high trap density of up to 1.6 × 1014 cm−2eV−1 is observed, which may be due to the lack of the cap layer causing the vulnerability to the subsequent high temperature annealing process.

https://iopscience.iop.org/article/10.1088/0256-307X/31/3/037302/pdf

Trap States in Al2O3 InAlN/GaN Metal-Oxide-Semiconductor Structures by Frequency-Dependent Conductance Analysis

Corrigendum to ‘Effect of post anode annealing on W/Au and Ni/Au multi-channel AlGaN/GaN Schottky diode’ [Superlattices and Microstructures 160 (2021) 107089]

In this letter, a parallel‐feedback dual‐band voltage‐controlled oscillator (DVCO) with low phase noise and a wide tuning range is proposed. The DVCO is composed of two tunable filters associated with four switches and an active device. By controlling four switches, the oscillation frequency can be switched and oscillated in one of two bands. The employed tunable filter with maintained passband shape and wide frequency tuning range (FTR) is beneficial to designing wideband DVCO with low phase noise. Owing to the maintained frequency response, the sharp phase variation and high in‐band group delay can be maintained during the filter tuning process, which can enhance the phase noise improvement. Moreover, the sharp phase variation can realize the phase compensation in a wide FTR when tuning the DVCO. To develop a DVCO with a simple circuit scheme, the two‐pole tunable filters with two different FTRs are designed. For verification, the proposed DVCO is designed, manufactured, and measured. The measurement results show that each band of the DVCO has a tuning range of 1.97–2.58 GHz (27.8%) and 2.934–3.468 GHz (16.7%), respectively. For the lower band, the phase noise at 100 kHz and 1 MHz frequency offset is better than −99.2 and −126.4 dBc/Hz, respectively. While for the upper band, the phase noise at 100 kHz and 1 MHz frequency offset is better than −101.2 and −127.4 dBc/Hz, respectively.

A low phase noise dual‐band voltage‐controlled oscillator based on switchable tunable filter

/pdf/a-novel-graphical-method-for-dual-frequency-two-sections-5gbccgp4nr.pdf

Xiaohua Ma

Papers

A Broadband Amplifier With Flat Bandwidth for Modulator and Measurement Driver Circuits

Trap States in Al2O3 InAlN/GaN Metal-Oxide-Semiconductor Structures by Frequency-Dependent Conductance Analysis

Corrigendum to ‘Effect of post anode annealing on W/Au and Ni/Au multi-channel AlGaN/GaN Schottky diode’ [Superlattices and Microstructures 160 (2021) 107089]

A low phase noise dual‐band voltage‐controlled oscillator based on switchable tunable filter

A Novel Graphical Method for Dual-Frequency Two Sections Transformer