Search results for "Lithium ion"
showing 10 items of 16 documents
Bis(2-ethylhexyl)phosphoric acid/bis(2-ethylhexyl)amine mixtures as solvent media for lithium-ions: A dynamical study
2016
Abstract The self-diffusion coefficient, the spin-lattice relaxation times and ionic conductivity of lithium ions in liquid mixtures composed of bis(2-ethylhexyl)amine (BEEA) and bis(2-ethylhexyl)phosphoric acid (HDEHP) have been thoroughly investigated as a function of composition and temperature by NMR spectroscopy and conductometry. While the temperature and composition dependence of diffusion coefficients of lithium ions follow the same trend observed for those of the surfactant molecules, the spin-lattice relaxation times of lithium ions and 1 H are remarkably different. The observed behavior has been interpreted in terms of lithium ions diffusion occurring through its association with…
Numerical and experimental validation of a LiFePO4 battery model at steady state and transient operations
2013
In the paper some of the battery models proposed in literature are analysed in order to predict the battery performance and, then, make sure that the Battery Management System (BMS) that is a key component to check and control the status of the batteries within their specified safe operating conditions, works in best conditions.
Iron and lithium-iron alkyl phosphates as nanostructured material for rechargeable batteries
2018
Abstract Inorganic/organic hybrid materials composed by iron atoms bonded to an alkyl phosphate can be easily synthesized by mixing at 110 °C iron chlorides with tri-alkyl phosphates. Since structural information on these products are lacking and taking into account that lithium/iron organic hybrid materials are important in lithium ion battery technology we report here the physico-chemical characterization of different hybrid lithium/iron butylphosphates. These materials are characterized by the presence of elongated hexagonal crystals stable up to 315 °C. The insertion of lithium does not affect the local structure. Thanks to such structures the material can be electrochemically-cycled an…
Nanostructured anode material for Li-ion batteries
2010
The present paper focuses on a nanostructured SnCo alloy electrochemically prepared by template method in view of its use as anode material alternative to graphite in lithium-ion batteries. The fabrication of SnCo nanowire arrays was carried out by potentiostatic co-deposition of the two metals by using nanostructured anodic alumina membranes as template. Electrochemical tests on lithiation-delithiation of these SnCo electrodes in conventional organic electrolyte (EC:DMC LiPF6) at 30°C showed that their specific capacity was stable for about the first 12 cycles at a value near to the theoretical one for Li22Sn5 and, hence, progressively decayed.
SnCo nanowire array as negative electrode for lithium-ion batteries
2011
Abstract Amorphous SnCo alloy nanowires (NWs) grown inside the channels of polycarbonate membranes by potentiostatic codeposition of the two metals (SnCo- PM ) were tested vs. Li by repeated galvanostatic cycles in ethylene carbonate-dimethylcarbonate – LiPF 6 for use as negative electrode in lithium ion batteries. These SnCo electrodes delivered an almost constant capacity value, near to the theoretical for an atomic ratio Li/Sn of 4.4 over more than 35 lithiation–delithiation cycles at 1 C. SEM images of fresh and cycled electrodes showed that nanowires remain partially intact after repeated lithiation–delithiation cycles; indeed, several wires expanded and became porous. Results of amorp…
Strategies and Techniques for Powering Wireless Sensor Nodes through Energy Harvesting and Wireless Power Transfer
2019
The continuous development of internet of things (IoT) infrastructure and applications is paving the way for advanced and innovative ideas and solutions, some of which are pushing the limits of state-of-the-art technology. The increasing demand for Wireless Sensor Nodes (WSNs) able to collect and transmit data through wireless communication channels, while often positioned in locations that are difficult to access, is driving research into innovative solutions involving energy harvesting (EH) and wireless power transfer (WPT) to eventually allow battery-free sensor nodes. Due to the pervasiveness of radio frequency (RF) energy, RF EH and WPT are key technologies with the potential to power …
An RF Wireless Power Transfer system to power battery-free devices for asset tracking
2019
Internet of Things (IoT) and Wireless Sensor Networks (WSN) infrastructures are becoming more and more available and diffused. One major outcome is the development of new services that help to make everyday life easier and better. One of those to which this paper reserves special attention is asset tracking which refers to the method of tracking physical assets. This service is very well based on IoT infrastructure and, due to the enormous number of objects to be traced, desperately needs the availability of inexpensive tags with sensing capabilities, that can be conveniently monitored from a long distance and require no maintenance. For this, engineers are called to face very challenging i…
Method for Producing an Electrode with Nanometric Structure and Electrode with Nanometric Stucture
2012
Nanostructured anode and cathode materials for Li-ion batteries
2010
Sn-Co nanowire-based anodes for lithium-ion batteries
2010
The demand of improvement in lithium-ion battery technology in terms of specific capacity and safety has stimulated the search for anode materials alternative to graphite. Among them, tin-based materials have been widely studied because tin can intercalate lithium up to atomic ratio Li/Sn of 4.4 to deliver a impressive specific capacity of 993 mAhg−1 (while graphite gives 372 mAhg−1). Unfortunately the high volume change of about 300%, which is related to the insertion/removal of lithium, causes the alloy pulverization and loss of electric contact that causes a poor cycle life. The synthesis of nanometric materials, intermetallic compounds and carbon composites are strategies that have been…