Power density

About: Power density is a research topic. Over the lifetime, 9534 publications have been published within this topic receiving 197264 citations. The topic is also known as: volumic power & volume power density.

Achieving high power factor and output power density in p-type half-Heuslers Nb1-xTixFeSb.

Abstract: Improvements in thermoelectric material performance over the past two decades have largely been based on decreasing the phonon thermal conductivity. Enhancing the power factor has been less successful in comparison. In this work, a peak power factor of ∼106 μW⋅cm−1⋅K−2 is achieved by increasing the hot pressing temperature up to 1,373 K in the p-type half-Heusler Nb0.95Ti0.05FeSb. The high power factor subsequently yields a record output power density of ∼22 W⋅cm−2 based on a single-leg device operating at between 293 K and 868 K. Such a high-output power density can be beneficial for large-scale power generation applications.

Flexible Ultrafast Aqueous Rechargeable Ni//Bi Battery Based on Highly Durable Single-Crystalline Bismuth Nanostructured Anode.

Abstract: A new type of ultrafast Ni//Bi battery with high flexibility and impressive electrochemical performance is demonstrated for the first time based on an as-prepared Bi electrode as the anode and a NiCo2 O4 nanowire electrode as the cathode. The NiCo2 O4 //Bi battery is able to deliver a remarkable energy density of 85.8 W h kg-1 at a power density of 1.02 kW kg-1 , and still retains 55.4 W h kg-1 when the power density is increased to 21.2 kW kg-1 .

A flexible solid-state zinc ion hybrid supercapacitor based on co-polymer derived hollow carbon spheres

Abstract: High electrochemical performance energy storage devices coupled with low cost and high safety operation are in urgent need due to the increasing demand for flexible and wearable electronics. For these applications lithium-ion and sodium-ion batteries are vastly limited due to their relatively low power density and security risks. On the other hand, conventional supercapacitors are suitable for flexible and wearable electronics due to their high power density while their low energy density has hindered their wide applications. Lithium or sodium ion hybrid supercapacitors are promising energy storage devices that benefit from the combined high energy density of batteries and high power density of supercapacitors. However, the use of organic electrolytes and shortage of lithium resources are expected to limit their widespread commercialization for flexible and wearable electronics. Here, for the first time, we introduce a safe and flexible solid-state zinc ion hybrid supercapacitor (ZHS) based on co-polymer derived hollow carbon spheres (HCSs) as the cathode, polyacrylamide (PAM) hydrogel as the electrolyte and Zn deposited on carbon cloth as the anode. Owing to the high surface area of the HCSs and the hollow structure which improves the ion adsorption and desorption kinetics of the cathode, the flexible solid-state ZHS delivers a highest capacity of 86.8 mA h g−1 and a maximum energy density of 59.7 W h kg−1 with a power density of 447.8 W kg−1. Besides, it displays excellent cycling stability with 98% capacity retention over 15 000 cycles at a current density of 1.0 A g−1. Moreover, the solid-state ZHS is flexible enough to sustain various deformations including squeezing, twisting and folding due to the use of flexible electrodes and electrolytes. Our study unveils a pioneering flexible solid-state ZHS with high safety, which is a promising candidate for flexible and wearable energy storage devices.

Optical Studies of Individual InAs Quantum Dots in GaAs: Few-Particle Effects

Abstract: Optical emission from individual strained indium arsenide (InAs) islands buried in gallium arsenide (GaAs) was studied. At low excitation power density, the spectra from these quantum dots consist of a single line. At higher excitation power density, additional emission lines appeared at both higher and lower energies, separated from the main line by about 1 millielectron volt. At even higher excitation power density, this set of lines was replaced by a broad emission peaking below the original line. The splittings were an order of magnitude smaller than the lowest single-electron or single-hole excited state energies, indicating that the fine structure results from few-particle interactions in the dot. Calculations of few-particle effects give splittings of the observed magnitude.