Nanoionics

Nanoionics[1] is the study and application of phenomena, properties, effects and mechanisms of processes connected with fast ion transport (FIT) in all-solid-state nanoscale systems. The topics of interest include fundamental properties of oxide ceramics at nanometer length scales, and fast ion conductor (advanced superionic conductor)/electronic conductor heterostructures.[2] Potential applications are in electrochemical devices (electrical double layer devices) for conversion and storage of energy, charge and information. The term and conception of nanoionics (as a new branch of science) were first introduced by A.L. Despotuli and V.I. Nikolaichik (Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka) in January 1992.[1]

A multidisciplinary scientific and industrial field of solid state ionics, dealing with ionic transport phenomena in solids, considers Nanoionics as its new division. [3] Nanoionics tries to describe, for example, diffusion&reactions, in terms which make sense only at a nanoscale, e.g., in terms of non-uniform (at a nanoscale) potential landscape.

There are two classes of solid state ionic nanosystems and two fundamentally different nanoionics: (I) nanosystems based on solids with low ionic conductivity, and (II) nanosystems based on advanced superionic conductors (e.g. alpha–AgI, rubidium silver iodide–family).[4] Nanoionics-I and nanoionics-II differ from each other in the design of interfaces. The role of boundaries in nanoionics-I is the creation of conditions for high concentrations of charged defects (vacancies and interstitials) in a disordered space-charge layer. But in nanoionics-II, it is necessary to conserve the original highly ionic conductive crystal structures of advanced superionic conductors at ordered (lattice-matched) heteroboundaries. Nanoionic-I can significantly enhance (up to ~10⁸ times) the 2D-like ion conductivity in nanostructured materials with structural coherence,[5] but it is remaining ~10³ times smaller relatively to 3D ionic conductivity of advanced superionic conductors.

The classical theory of diffusion and migration in solids is based on the notion of a diffusion coefficient, activation energy [6] and electrochemical potential. [7] This means that accepted is the picture of a hopping ion transport in the potential landscape where all barriers are of the same height (uniform potential relief). In spite of the obvious difference of objects of solid state ionics and nanoionics-I, -II, the true new problem of fast ion transport and charge/energy storage (or transformation) for these objects (fast ion conductors) has a special common basis: non-uniform potential landscape on nanoscale (for example [8]) which determines the character of the mobile ion subsystem response to an impulse or harmonic external influence, e.g. a weak influence in Dielectric spectroscopy (impedance spectroscopy).[9]

Characteristics

Being a branch of nanoscience and nanotechnology, nanoionics is unambiguously defined by its own objects (nanostructures with FIT), subject matter (properties, phenomena, effects, mechanisms of processes, and applications connected with FIT at nano-scale), method (interface design in nanosystems of superionic conductors), and criterion (R/L ~1, where R is the length scale of device structures, and L is the characteristic length on which the properties, characteristics, and other parameters connected with FIT change drastically).

The International Technology Roadmap for Semiconductors (ITRS) relates nanoionics-based resistive switching memories to the category of "emerging research devices" ("ionic memory"). The area of close intersection of nanoelectronics and nanoionics had been called nanoelionics (1996). Now, the vision of future nanoelectronics constrained solely by fundamental ultimate limits is being formed in advanced researches.[10][11][12][13] The ultimate physical limits to computation[14] are very far beyond the currently attained (10¹⁰ cm⁻², 10¹⁰ Hz) region. What kind of logic switches might be used at the near nm- and sub-nm peta-scale integration? The question was the subject matter already in,[15] where the term "nanoelectronics" [16] was not used yet. Quantum mechanics constrains electronic distinguishable configurations by the tunneling effect at tera-scale. To overcome 10¹² cm⁻² bit density limit, atomic and ion configurations with a characteristic dimension of L <2 nm should be used in the information domain and materials with an effective mass of information carriers m* considerably larger than electronic ones are required: m* =13 m_e at L =1 nm, m* =53 m_e (L =0,5 nm) and m* =336 m_e (L =0,2 nm).[13] Future short-sized devices may be nanoionic, i.e. based on the fast ion transport at the nanoscale, as it was first stated in.[1]

Examples

The examples of nanoionic devices are all-solid-state supercapacitors with fast ion transport at the functional heterojunctions (nanoionic supercapacitors),[4][17] lithium batteries and fuel cells with nanostructured electrodes,[18] nano-switches with quantized conductivity on the basis of fast ion conductors[19][20] (see also memristors and programmable metallization cell). These are well compatible with sub-voltage and deep-sub-voltage nanoelectronics [21] and could find wide applications, for example in autonomous micro power sources, RFID, MEMS, smartdust, nanomorphic cell, other micro- and nanosystems, or reconfigurable memory cell arrays.

An important case of fast ionic conduction in solid states is that in surface space-charge layer of ionic crystals. Such conduction was first predicted by Kurt Lehovec.[22] A significant role of boundary conditions with respect to ionic conductivity was first experimentally discovered by C.C. Liang[23] who found an anomalously high conduction in the LiI-Al₂O₃ two-phase system. Because a space-charge layer with specific properties has nanometer thickness, the effect is directly related to nanoionics (nanoionics-I). The Lehovec effect has become the basis for the creation of a multitude of nanostructured fast ion conductors which are used in modern portable lithium batteries and fuel cells. In 2012, a 1D structure-dynamic approach was developed in nanoionics[24][25][26] for detailed description of the space charge formation and relaxation processes in irregular potential relief (direct problem) and interpretation of characteristics of nanosystems with fast ion transport (inverse problem), as example, for the description of a collective phenomenon: coupled ion transport and dielectric-polarization processes which lead to A. K. Jonscher's "universal" dynamic response.

See also

• Programmable metallization cell

References

1. Despotuli, A.L.; Nikolaichic V.I. (1993). "A step towards nanoionics". Solid State Ionics. 60 (4): 275–278. doi:10.1016/0167-2738(93)90005-N.
2. Yamaguchi, S. (2007). "Nanoionics - Present and future prospects". Science and Technology of Advanced Materials. 8 (6): 503 (free download). Bibcode:2007STAdM...8..503Y. doi:10.1016/j.stam.2007.10.002.
3. C S Sunandana (2015). Introduction to Solid State Ionics: Phenomenology and Applications (First ed.). CRC Press. p. 529. ISBN 9781482229707.
4. Despotuli, A.L.; Andreeva, A.V.; Rambabu, B. (2005). "Nanoionics of advanced superionic conductors". Ionics. 11 (3–4): 306–314. doi:10.1007/BF02430394.
5. Garcia-Barriocanal, J.; Rivera-Calzada A.; Varela M.; Sefrioui Z.; Iborra E.; Leon C.; Pennycook S. J.; Santamaria1 J. (2008). "Colossal ionic conductivity at interfaces of epitaxial ZrO₂:Y₂O₃/SrTiO₃ heterostructures". Science. 321 (5889): 676–680. Bibcode:2008Sci...321..676G. doi:10.1126/science.1156393. PMID 18669859.
6. H Mehrer (2007). Diffusion in solids (First ed.). Springer-Verlag Berlin Heidelberg. p. 651. ISBN 978-3-540-71488-0.
7. A D McNaught (1997). IUPAC. Compendium of Chemical Terminology (the Gold Book) (2nd ed.). Blackwell Scientific Publications. p. 1622. ISBN 978-0-9678550-9-7.
8. 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.
9. Despotuli, A.; Andreeva A. (2015). "Maxwell displacement current and nature of Jonsher's "universal" dynamic response in nanoionics". Ionics. 21 (2): 459–469. arXiv:1403.4818. doi:10.1007/s11581-014-1183-3.
10. Cavin, R.K.; Zhirnov V.V. (2006). "Generic device abstractions for information processing technologies". Solid-State Electronics. 50 (4): 520–526. Bibcode:2006SSEle..50..520C. doi:10.1016/j.sse.2006.03.027.
11. Cerofolini, G.F. (2007). "Realistic limits to computation. I. Physical limits". Appl. Phys. A. 86 (1): 23–29. Bibcode:2007ApPhA..86...23C. doi:10.1007/s00339-006-3670-5.
12. Cerofolini, G.F.; Romano E. (2008). "Molecular electronic in silico". Appl. Phys. A. 91 (2): 181–210. Bibcode:2008ApPhA..91..181C. doi:10.1007/s00339-008-4415-4.
13. Zhirnov, V.V.; Cavin R.K. (2007). "Emerging research nanoelectronic devices: the choice of information carrier". ECS Transactions. 11: 17–28. CiteSeerX 10.1.1.1019.3697. doi:10.1149/1.2778363.
14. Lloyd, S. (2000). "Ultimate physical limits to computation". Nature. 406 (6799): 1047–1054. arXiv:quant-ph/9908043. Bibcode:2000Natur.406.1047L. doi:10.1038/35023282. PMID 10984064.
15. Chiabrera, A.; Di Zitti, E.; Costa, F.; Bisio, G.M. (1989). "Physical limits of integration and information processing in molecular systems". J. Phys. D: Appl. Phys. 22 (11): 1571–1579. Bibcode:1989JPhD...22.1571C. doi:10.1088/0022-3727/22/11/001.
16. Bate, R. T.; Reed M. A.; Frensley W. R (August 1987). "Nanoelectronics (in Final technical rept., http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA186969 Corporate Author : TEXAS INSTRUMENTS INC DALLAS)". Cite journal requires |journal= (help); External link in |title= (help)
17. Despotuli, A.L., Andreeva A.V. (2007). "High-value capacitors for 0.5-V nanoelectronics". Modern Electronics. № 7: 24–29. Russian:"Archived copy". Archived from the original on 2007-11-05. Retrieved 2007-10-13.CS1 maint: archived copy as title (link) English translation:
18. Maier, J. (2005). "Nanoionics: ion transport and electrochemical storage in confined systems". Nature Materials. 4 (11): 805–815. Bibcode:2005NatMa...4..805M. doi:10.1038/nmat1513. PMID 16379070.
19. Banno, N.; Sakamoto, T.; Iguchi, N.; Kawaura, H.; Kaeriyama, S.; Mizuno, M.; Terabe, K.; Hasegawa, T.; Aono, M. (2006). "Solid-Electrolyte Nanometer Switch". IEICE Transactions on Electronics. E89-C(11) (11): 1492–1498. Bibcode:2006IEITE..89.1492B. doi:10.1093/ietele/e89-c.11.1492.
20. Waser, R.; Aono, M. (2007). "Nanoionics-based resistive switching memories". Nature Materials. 6 (11): 833–840. Bibcode:2007NatMa...6..833W. doi:10.1038/nmat2023. PMID 17972938.
21. http://www.nanometer.ru/2008/02/08/nanoelektronika_5900.html
22. Lehovec, K. (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.
23. Liang, C. C. (1973). "Conduction Characteristics of the Lithium Iodide-Aluminum Oxide Solid Electrolytes". J. Electrochem. Soc. 120 (10): 1289–1292. doi:10.1149/1.2403248.
24. http://www.nanometer.ru/2013/08/22/nanoionika_333471.html
25. Despotuli, Alexandr; Andreeva, Alexandra (2013). "Structure-dynamic approach in nanoionics. Modeling of ion transport on blocking electrode". arXiv:1311.3480 [cond-mat.mtrl-sci].
26. Despotuli, A.; Andreeva A.V. (2016). "Method of uniform effective field in structure-dynamic approach of nanoionics". Ionics. 22 (8): 1291–1298. doi:10.1007/s11581-016-1668-3.