Фаст-ионный дирижер
В материаловедения области быстрые ионные проводники представляют собой твердые проводники с очень мобильными ионами . Эти материалы важны в области ионики твердого состояния , а также известны как твердые электролиты и суперионные проводники . Эти материалы полезны в батареях и различных датчиках. Быстрые ионные проводники используются главным образом в твердых оксидных топливных элементах . Как твердые электролиты, они позволяют перемещать ионы без необходимости в жидкой или мягкой мембране, разделяющей электроды. Это явление опирается на прыжок ионов через жесткую кристаллическую структуру .
Механизм
[ редактировать ]Быстрые ионные проводники носят промежуточный характер между кристаллическими твердыми веществами, которые обладают регулярной структурой с неподвижными ионами, и жидкими электролитами , которые не имеют регулярной структуры и полностью подвижных ионов. Сплошные электролиты находят использование во всех твердотельных суперконденсаторах , батареях и топливных элементах , а также в различных видах химических датчиков .
Классификация
[ редактировать ]В твердых электролитах (очках или кристаллах) ионная проводимость σ I может быть любым значением, но она должна быть намного больше, чем электронная. Обычно твердые тела, где σ I на порядок от 0,0001 до 0,1 Ом −1 см −1 (300 К) называются супероническими проводниками.
Протонные дирижеры
[ редактировать ]Протонные проводники представляют собой специальный класс твердых электролитов, где ионы водорода действуют в качестве носителей заряда. Одним из заметных примеров является супероническая вода .
Superionic conductors
[edit]Superionic conductors where σi is more than 0.1 Ω−1 cm−1 (300 K) and the activation energy for ion transport Ei is small (about 0.1 eV), are called advanced superionic conductors. The most famous example of advanced superionic conductor-solid electrolyte is RbAg4I5 where σi > 0.25 Ω−1 cm−1 and σe ~10−9 Ω−1 cm−1 at 300 K.[1][2] The Hall (drift) ionic mobility in RbAg4I5 is about 2×10−4 cm2/(V•s) at room temperatures.[3] The σe – σi systematic diagram distinguishing the different types of solid-state ionic conductors is given in the figure.[4][5]
No clear examples have been described as yet, of fast ion conductors in the hypothetical advanced superionic conductors class (areas 7 and 8 in the classification plot). However, in crystal structure of several superionic conductors, e.g. in the minerals of the pearceite-polybasite group, the large structural fragments with activation energy of ion transport Ei < kBT (300 К) had been discovered in 2006.[6]
Examples
[edit]Zirconia-based materials
[edit]A common solid electrolyte is yttria-stabilized zirconia, YSZ. This material is prepared by doping Y2O3 into ZrO2. Oxide ions typically migrate only slowly in solid Y2O3 and in ZrO2, but in YSZ, the conductivity of oxide increases dramatically. These materials are used to allow oxygen to move through the solid in certain kinds of fuel cells. Zirconium dioxide can also be doped with calcium oxide to give an oxide conductor that is used in oxygen sensors in automobile controls. Upon doping only a few percent, the diffusion constant of oxide increases by a factor of ~1000.[7]
Other conductive ceramics function as ion conductors. One example is NASICON, (Na3Zr2Si2PO12), a sodium super-ionic conductor
beta-Alumina
[edit]Another example of a popular fast ion conductor is beta-alumina solid electrolyte.[8] Unlike the usual forms of alumina, this modification has a layered structure with open galleries separated by pillars. Sodium ions (Na+) migrate through this material readily since the oxide framework provides an ionophilic, non-reducible medium. This material is considered as the sodium ion conductor for the sodium–sulfur battery.
Fluoride ion conductors
[edit]Lanthanum trifluoride (LaF3) is conductive for F− ions, used in some ion selective electrodes. Beta-lead fluoride exhibits a continuous growth of conductivity on heating. This property was first discovered by Michael Faraday.
Iodides
[edit]A textbook example of a fast ion conductor is silver iodide (AgI). Upon heating the solid to 146 °C, this material adopts the alpha-polymorph. In this form, the iodide ions form a rigid cubic framework, and the Ag+ centers are molten. The electrical conductivity of the solid increases by 4000x. Similar behavior is observed for copper(I) iodide (CuI), rubidium silver iodide (RbAg4I5),[9] and Ag2HgI4.
Other Inorganic materials
[edit]- Silver sulfide, conductive for Ag+ ions, used in some ion selective electrodes
- Lead(II) chloride, conductive for Cl- ions at higher temperatures[10]
- Some perovskite ceramics – strontium titanate, strontium stannate – conductive for O2− ions
- – conductive for H+ ions
- (hydrogen uranyl phosphate tetrahydrate) – conductive for H+ ions
- Cerium(IV) oxide – conductive for O2− ions
Organic materials
[edit]- Many gels, such polyacrylamides, agar, etc. are fast ion conductors[11][12]
- A salt dissolved in a polymer – e.g. lithium perchlorate in polyethylene oxide[13]
- Polyelectrolytes and Ionomers – e.g. Nafion, a H+ conductor
History
[edit]The important case of fast ionic conduction is one in a surface space-charge layer of ionic crystals. Such conduction was first predicted by Kurt Lehovec.[14] As a space-charge layer has nanometer thickness, the effect is directly related to nanoionics (nanoionics-I). Lehovec's effect is used as a basis for developing nanomaterials for portable lithium batteries and fuel cells.
See also
[edit]References
[edit]- ^ Akin, Mert; Wang, Yuchen; Qiao, Xiaoyao; Yan, Zhiwei; Zhou, Xiangyang (September 2020). "Effect of relative humidity on the reaction kinetics in rubidium silver iodide based all-solid-state battery". Electrochimica Acta. 355: 136779. doi:10.1016/j.electacta.2020.136779. S2CID 225553692.
- ^ Wang, Yuchen; Akin, Mert; Qiao, Xiaoyao; Yan, Zhiwei; Zhou, Xiangyang (September 2021). "Greatly enhanced energy density of all‐solid‐state rechargeable battery operating in high humidity environments". International Journal of Energy Research. 45 (11): 16794–16805. doi:10.1002/er.6928.
- ^ Stuhrmann C.H.J.; Kreiterling H.; Funke K. (2002). "Ionic Hall effect measured in rubidium silver iodide". Solid State Ionics. 154–155: 109–112. doi:10.1016/S0167-2738(02)00470-8.
- ^ Александр Деспотули; Александра Андреева (2007). Высокоёмкие конденсаторы для 0,5 вольтовой наноэлектроники будущего. Современная Электроника (in Russian) (7): 24–29. Alexander Despotuli; Alexandra Andreeva (2007). "High-capacity capacitors for 0.5 voltage nanoelectronics of the future". Modern Electronics (7): 24–29.
- ^ Despotuli, A.L.; Andreeva, A.V. (January 2009). "A Short Review on Deep-Sub-Voltage Nanoelectronics and Related Technologies". International Journal of Nanoscience. 8 (4&5): 389–402. Bibcode:2009IJN.....8..389D. doi:10.1142/S0219581X09006328.
- ^ Bindi, L.; Evain M. (2006). "Fast ion conduction character and ionic phase-transitions in disordered crystals: the complex case of the minerals of the pearceite– polybasite group". Phys Chem Miner. 33 (10): 677–690. Bibcode:2006PCM....33..677B. doi:10.1007/s00269-006-0117-7. S2CID 95315848.
- ^ Shriver, D. F.; Atkins, P. W.; Overton, T. L.; Rourke, J. P.; Weller, M. T.; Armstrong, F. A. “Inorganic Chemistry” W. H. Freeman, New York, 2006. ISBN 0-7167-4878-9.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Akin, Mert; Wang, Yuchen; Qiao, Xiaoyao; Yan, Zhiwei; Zhou, Xiangyang (20 September 2020). "Effect of relative humidity on the reaction kinetics in rubidium silver iodide based all-solid-state battery". Electrochimica Acta. 355: 136779. doi:10.1016/j.electacta.2020.136779. S2CID 225553692.
- ^ Matsumoto, Hiroshige; Miyake, Takako; Iwahara, Hiroyasu (2001-05-01). "Chloride ion conduction in PbCl2-PbO system". Materials Research Bulletin. 36 (7): 1177–1184. doi:10.1016/S0025-5408(01)00593-1. ISSN 0025-5408.
- ^ "The Roll-to-Roll Battery Revolution". Ev World. Archived from the original on 2011-07-10. Retrieved 2010-08-20.
- ^ Perzyna, K.; Borkowska, R.; Syzdek, J. A.; Zalewska, A.; Wieczorek, W. A. A. (2011). "The effect of additive of Lewis acid type on lithium–gel electrolyte characteristics". Electrochimica Acta. 57: 58–65. doi:10.1016/j.electacta.2011.06.014.
- ^ Syzdek, J. A.; Armand, M.; Marcinek, M.; Zalewska, A.; Żukowska, G. Y.; Wieczorek, W. A. A. (2010). "Detailed studies on the fillers modification and their influence on composite, poly(oxyethylene)-based polymeric electrolytes". Electrochimica Acta. 55 (4): 1314. doi:10.1016/j.electacta.2009.04.025.
- ^ Lehovec, Kurt (1953). "Space-charge layer and distribution of lattice defects at the surface of ionic crystals". Journal of Chemical Physics. 21 (7): 1123–1128. Bibcode:1953JChPh..21.1123L. doi:10.1063/1.1699148.
