Topic
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.
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TL;DR: In this article, a solid-state flexible aqueous Zn-ion battery was fabricated with nanostructured polyaniline-cellulose papers as the cathode and Zn grown graphite papers as anode.
Abstract: Solid-state flexible aqueous Zn-ion battery was fabricated with nanostructured polyaniline–cellulose papers as the cathode and Zn-grown graphite papers as the anode. The separator was a flexible gel electrolyte with high ionic conductivity, based on cellulose nanofibers. The Zn-ion battery exhibited energy density of 117.5 and 67.8 mW·h/g at power density of 0.16 and 3.34 W/g, respectively (estimated from total active mass of both cathode and anode). The energy density of the Zn-ion battery was much higher than that of asymmetric supercapacitors with aqueous electrolytes, while maintaining a comparable power density. Meanwhile, good cyclic stability was achieved with a high capacity retention of 84.7% after 1000 charge/discharge cycles at a current density of 4 A/g. More importantly, specific capacity changed little under mechanical bending, and there was only 9% loss after 1000 bending cycles. The solid-state flexible Zn-ion battery has great potential as an energy-storage device for flexible displays an...
88 citations
TL;DR: A flexible and wearable thermoelectric nanogenerator made from Bi2Te3, which allows high voltage and output power density, and is temperature-sensitive thus can be used for temperature measurement with a resolution of 0.5K, which may have important prospects in flexible wearable physical sensors and individualized medical care.
Abstract: We propose a flexible and wearable thermoelectric nanogenerator (FTEG) made from Bi2Te3, which allows high voltage and output power density. The proposed FTEG works as a thermopile with the end-to-...
88 citations
TL;DR: In this article, a new performance analysis is applied to a reversible Carnot cycle based on a new criterion which is proposed for all kind of heat engines, and the proposed criterion, called efficient power, is defined as the multiplication of power by efficiency.
Abstract: Many performance analyses have been carried out based on two comparative criteria namely maximum power (mp) and maximum power density (mpd). Researchers involved in power maximization studies have utilized the thermal efficiency at mp (Curzon–Ahlborn efficiency) as an efficiency standard for practical heat engines. On the other hand, maximum power density studies showed that the efficiency at mpd is always greater than that at the mp, while the power output from heat engines reduces. In this study, a new performance analysis is applied to a reversible Carnot cycle based on a new criterion which is proposed for all kind of heat engines. The proposed criterion, called efficient power, is defined as the multiplication of power by efficiency. This criterion considers not only the power output, but also the cycle efficiency. Maximizing the efficient power gives a compromise between power and efficiency. The results showed that the design parameters at maximum efficient power (mep) conditions lead to mo...
88 citations
TL;DR: A thermally regenerative ammonia battery is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes that indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%.
Abstract: A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72 °C produced a power density of 236±8 W m−2, with a linear decrease in power to 95±5 W m−2 at 23 °C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Wh m−3 at a discharge energy efficiency of 54 % and a temperature of 37 °C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13 % and an overall thermal energy recovery of 0.5 %. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.
87 citations
TL;DR: In this paper, a high phosphorus-doped wood-derived carbon thick electrode for supercapacitor via phytic acid treatment, which can form hydrogen bonds with cellulose molecules in the wood, was reported.
87 citations