Electrochemical Insertion of Li and Na Ions into Nanocrystalline Fe[sub 3]O[sub 4] and α-Fe[sub 2]O[sub 3] for Rechargeable Batteries

2010 ◽  
Vol 157 (1) ◽  
pp. A60 ◽  
Author(s):  
Shinichi Komaba ◽  
Takashi Mikumo ◽  
Naoaki Yabuuchi ◽  
Atsushi Ogata ◽  
Hiromi Yoshida ◽  
...  
2013 ◽  
Vol 6 (7) ◽  
pp. 2067 ◽  
Author(s):  
Sung You Hong ◽  
Youngjin Kim ◽  
Yuwon Park ◽  
Aram Choi ◽  
Nam-Soon Choi ◽  
...  

2021 ◽  
Author(s):  
Pan Xiong ◽  
Fan Zhang ◽  
Xiuyun Zhang ◽  
Yifan Liu ◽  
Yunyan Wu ◽  
...  

Abstract Atomic-scale regulation of both cationic and anionic transport is of great significance in membrane-based separation technologies. Ionic transport regulation techniques could also play a crucial role in developing high-performance alkali metal batteries such as alkali metal-sulfur and alkali metal-selenium batteries, which suffer from the non-uniform transport of alkali metal ions and detrimental shuttling of polysulfide/polyselenide (PS) anions. These obstacles can cause severe growth of alkali metal dendrites and the irreversible consumption of active cathodes, leading to capacity decay and short cycling life. Herein, we report long-life alkali metal batteries enabled by atomic-scale tandem regulation of the migration of both alkali metal cations (Li+/Na+) and PS anions using negatively charged Ti0.87O2 nanosheets with Ti atomic vacancies. The shuttling of PS anions has been effectively eliminated via a robust electrostatic repulsion between the negatively charged nanosheets and PS anions. The negatively charged nanosheets can also regulate the migration of Li+/Na+ ions to ensure a homogeneous ion flux through efficient but light adhesion of Li+/Na+ ions within the nanosheets. The atomic Ti vacancies act as sub-nanometre pores to provide fast diffusion channels for Li+/Na+ ions. Therefore, eradication of PS shuttling and stable Li/Na-ion diffusion without compromising the fast transport of Li+/Na+ ions has been achieved for long-life alkali metal-sulfur and alkali metal-selenium batteries. This work provides a facile and effective strategy to regulate the transport of both cations and anions for developing advanced rechargeable batteries by using two-dimensional vacancy-enhanced materials.


ChemInform ◽  
2014 ◽  
Vol 45 (22) ◽  
pp. no-no ◽  
Author(s):  
Sung You Hong ◽  
Youngjin Kim ◽  
Yuwon Park ◽  
Aram Choi ◽  
Nam-Soon Choi ◽  
...  

2014 ◽  
Vol 26 (3-4) ◽  
pp. 42-61
Author(s):  
O. G. Lucyshyn ◽  
I. K. Teslenko

The recent ecological situation of Kyiv megalopolis has a special specific of environment technogenic pollution as a chemical features and content of polluting phytotoxicants. During 2007–2012, our observation revealed what the most dangerous factors which have harm impact on the street woody plants are the huge concentration of phytotoxic elements (Na+, Cl-, Pb2+, Cd2+). Nowadays, the technogenic impact on the megalopolyisis surrounding comes to the dangerous, even, catastrophic level. The main reason of total and chloral necrose of leaves, the summer defoliation of crown and major tree's death is the over pollution of the soil and plant's phytomass by phytotoxic elements, the concentration of which by standards evaluation and by trees reactions are critical and exists at the level of adaptation possibility and survival. The main sources of Pb2+ and Cd2+ ions are transport outcomes (> 90 % of total technogenic pollution). The increasing of Pb2+ and Cd2+ in the soil is depended from intensivity of transport outcomes, using of ethylated petrol, and location of trees along roads as well as from the trees species. Continuously increasing of number of cars at the city streets is accompanying with similar increasing of ions concentration. Thus, in the soil around root system of street woody plants, depending from their location along roads, the concentration of Pb2+ (moving form) is between 41,7 (I. Kudri str.) and 102,6 mg\kg of soil (Nauki avenue). It exceeds the maximum permissible concentration (MPC), which is 20,8–51,3 mg\kg of soil. Next, for Norway maple (Acer platanoides) the concentration of Pb2+ in the soil varies from 41,7 to 80,5 mg / kg of soil in the area of the root system and it is around 20,8–40,2 MPC. In the leaves of this tree it is 7,83–13,5 mg / kg of dry mass (MPC is 15,8–27,0). For the horse chestnut (Aedculus hippocastanum) at the Nauka avenue, the concentration of plumbum in the root is 13,4 mg / kg (MPC is 26,8), in the cortex – 17,7 mg / kg (MPC is 35,4), in leaves – 8,21 mg / kg (MPC is 16,4), which by the normative evaluation are the critical concentrations. The source of Na+ and Cl-, which is a new factor for Kyiv megalopolis, is irregular load of high concentrations of industrial salt NaCl into the environment, as a way against black ice in winter time, where the Na+ ions ( mobile form) is in the high concentrations in leaves (0,76 % for Norway maple (Acer platanoides) on the I. Kudri str., 1,28 % – small-leaved linden (Tilia cordata) at the 40-richya Zhovtnya ave, 2,0 % – horse chestnut (Aedculus hippocastanum) at the Nauki ave), those are exceeded the concentration of the element comparing to the control test object, respectively, in 10,6, 12,8 and 5,0 times. Na+ ions are an aggressive phytotoxins and the main factor of leaves necrose of tree crown (within 70–100 % necrosis leaves in the crown). Degradation and total reduction of the specific weight of plants in the megalopolis environment are decrease the cleaning role of the street tree plants, which are the main alive filters for soil and air cleaning, as well as the main bioaccumulators and detoxicants of harm substances of anthropogenic pollution. Species adaptive specificity is revealed at the bioaccumulation level and the selective locality of phytotoxic elements (Na+, Cl-, Pb2+, Cd2+, agile form) in technourbanhabitats-pic conditions, there dominated bioaccumulation and localization of Na+ ions by trees assimilative system is caused the adaptive orientation of endogenic and intraspecific variability of phytoindicative morphophysiologic features of plants functional condition under the stressing factors. This also is defined the sensitivity of small-leaved linden (Tilia cordata Mill.), norway maple (Acer platanoides L.) and horse chestnut (Aesculus hippocastanum L.) to the big concentration of potassium as the most danger one for the plant survival. The biggest accumulation of Na+ ions at the roots of Lombardy poplar (Populus pyramidalis Roz.), Bolle's poplar (Populus bolleana Lauche) and sugar maple (Acer saccharinum L.) is lead to a higher resistance of their assimilation system. At the technourbohabitate-pic conditions, the level of realization of ontogenetic and phylogenetic adaptive capacity of the sensitive species of trees is harmfully low (21,3–44,3 %). It is at the level of survival/death of plants. The street Lombardy poplar, Bolle's poplar and sugar maple, despite of more higher level of their adaptation (68,4–87,7 %), still also can't fully adapt to the critical levels of technogenic pollution of megalopolis environment. 


Author(s):  
S. G. Obukhov ◽  
I. A. Plotnikov ◽  
V. G. Masolov

The paper presents the results of the comparative analysis of operation modes of an autonomous hybrid power complex with/without the energy store. We offere the technique which defines the power characteristics of the main components of a hybrid power complex: the consumers of the electric power, wind power and photo-electric installations (the last ones have been constructed). The paper establishes that, in order to compensate the seasonal fluctuations of power in autonomous power systems with renewable energy resources, the accumulative devices are required, with a capacity of tens of MWh including devices that are capable to provide energy storage with duration about half a year. This allows abandoning the storage devices for smoothing the seasonal fluctuations in the energy balance.The analysis of operation modes of energy stores has shown that for a stock and delivery of energy on time intervals, lasting several hours, the accumulative devices with rather high values of charging and digit power aren't required. It allows using the lead-acid rechargeable batteries of the deep category for smoothing the daily peaks of surplus and a capacity shortage. Moreover, the analysis of operation modes of energy stores as a part of the hybrid complexes has demonstrated that in charging/digit currents of the energy store the low-frequency and high-frequency pulsations of big amplitude caused by changes of size of output power of the renewable power installations and loading are inevitable. If low-frequency pulsations (the period of tens of minutes) can partially be damped due to the restriction of size of the maximum charging current of rechargeable batteries, then it is essentially impossible to eliminate high-frequency pulsations (the period of tens of seconds) in the power systems with the only store of energy. The paper finds out that the combined energy store having characteristics of the accumulator in the modes of receiving and delivery of power on daily time intervals, and at the same time having properties of the supercondenser in the modes of reception and return of impulses of power on second intervals of time is best suited to requirements of the autonomous power complexes with renewable energy resources.


2020 ◽  
Vol 65 (6) ◽  
pp. 1058-1064
Author(s):  
С.В. Пастон ◽  
◽  
А.М. Поляничко ◽  
О.В. Шуленина ◽  
Д.Н. Осинникова ◽  
...  

The aqueous environment and ionic surrounding are the most important factors determining the conformation of DNA and its functioning in the cell. The specificity of the interaction between DNA and cations is especially pronounced with a decrease in water activity. In this work, we studied the B-A transition in high molecular weight DNA with a decrease of humidity in the film with different contents of Na+ ions using FTIR spectroscopy. The IR spectrum of DNA is not only very sensitive to the state of its secondary structure, but also allows us to estimate the amount of water bound to DNA. Upon dehydration of the DNA film, changes characteristic of the B-A transition were observed in the IR absorption spectrum. Using thermogravimetric analysis, it was shown that the degree of DNA hydration reaches the saturation level at a relative humidity of 60% and decreases slightly upon further drying. It has been established that with increasing Na+ concentration, the amount of water strongly bound to DNA decreases. Along with it, sodium ions destroy the hydration shell of DNA and are able to interact directly with phosphate groups.


1981 ◽  
Vol 46 (10) ◽  
pp. 2354-2363 ◽  
Author(s):  
Svatomír Kmošták ◽  
Karel Setínek

The catalytic activity of sulphonated macroporous styrene-divinylbenzene copolymers, the exchange capacity of which was neutralized from 30, 50 and 80% by Fe(III) ions and from 30% by Na ions and that of Wofatit Y-37 ion exchanger neutralized from 10% of its total exchange capacity by several transition metal ions and by sodium has been studied in isomerisation of cyclohexene and dehydration of 1-propanol in the gas phase at 130 °C. It was demonstrated that in both reactions transition metal ions exhibit additional effect to the expected neutralization of the polymer acid groups. In the case of cyclohexene isomerization, this effect depends on the degree of crosslinking of polymer mass of the catalyst. Such dependence has not been, however, observed in dehydration of 1-propanol. The type of transition metal ions did not exhibit any significant effect on the catalytic activity of the polymer catalysts studied.


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