A step towards nanoionics

Rambabu

2005

Ionics

Abstract. New scientific direction -nanoionics of advanced superionic conductors (ASICs) was proposed. Nanosystems of solid state ionics were divided onto two classes differing by an opposite influence of crystal structure defects on the ionic conductivity oi (energy activation E): 1) nanosystems on the base compounds with initial small o~ (large values of E); and II) nanosystems of ASICs (nano-ASICs) with E = 0.1 eV.The fundamental challenge of nanoionics as the conservation of fast ion transport (FIT) in nano-ASICs on the level of bulk crystal was first recognized and for the providing of FIT in nanoASICs the conception of structure-ordered (coherent) ASIC//indifferent electrode (IE) heteroboundaries was proposed. Nano-ASIC characteristic parameter P = d/Xo (d is the thickness of ASIC layer with the defect crystal structure at the heteroboundary, and Ao is the screening length of charge for mobile ions of the bulk of ASIC) was introduced. The criterion for a conservation of FIT in nano-ASIC is P = 1. It was shown that at the equilibrium conditions the contact potentials V at the ASIC//IE coherent heterojunctions in nano-ASICs are V << keT/e. Interface engineering approach "from advanced materials to advanced devices" was proposed as fundamentals for the development of applied nanoionics. The possibility for creation on the base of ASIC//IE coherent heterojunctions of the efficient energy and power devices (sensors and supercapacitors with specific capacity ~10 -~ F/cm 2 and maximal frequencies 10~-109 Hz,) suited for micro(nano)electronics, microsystem technology and 5 Gbit DRAM was pointed out.

Section: Introductionmentioning

confidence: 99%

Nanoionics of advanced superionic conductors

Rambabu

2005

Ionics

“…Micron-sized carbon-based integrated on chip nanoionic SCs [1,5] as well as the surface mount high-capacity SCs [6,51] for portable electronics may be well compatible with future nanoelectronics technologies. Nanoionic devices first proposed by IMT RAS ("The results obtained show that it is possible to form arrays of electrochemical devices with single elements ∼ 10 nm in size in the films" [52] are now in the scope of interest of ITRS [53]. Future deep-sub-voltage nanoelectronics [11] will use nanoionic SCs [1] which are in scope of Samsung's interest [54] now.…”

Section: Quantum Capacitance Of Advanced Carbon Electrode Nanostructuresmentioning

confidence: 99%

Electrode Nanostructures for Advanced Supercapacitors

2011

Acta Phys. Pol. A

The ultimate physical limit approach is applied to the case of electrode nanostructures of double electric layer (DEL) supercapacitors (SCs) on the basis of advanced superionic conductors (AdSIC) required for the development of many high-tech directions. New nanoionic fundamentals (notion, criteria and estimations) are introduced and the ways for the creation of advanced carbon-based nanostructures suited for different types of SCs are proposed.

“…Introduction of the notion of the local Maxwell displacement currents [22,24] into the nanoionics concept [26] permits a new viewpoint on the dynamic phenomena and effects which nature and mechanisms remain poorly understood. One of still unsolved problem of solid state ionics is the -universal‖ dynamic response.…”

Section: Jonsher's "Universal" Dynamic Response In Nanoionicsmentioning

confidence: 99%

“…Recently, a structure-dynamic approach [20][21][22][23][24][25] has been proposed for the development of nanoionics [26], particularly, for detailed description of processes in the region of EC/AdSIC coherent ideally polarizable heterojunctions. The approach includes a structure-dynamic model of a nanostructure, a method of -hidden‖ variables and a physico-mathematical formalism which operates these variables.…”

Section: Introductionmentioning

confidence: 99%

“…In [19] the attention is drawn to the fact that the Maxwell displacement current should be taken into account for the process of EDL charging. However, this fundamental current has not been even mentioned in the reviews [2-4] devoted to multiple-aspect discussions on dynamic properties of solid ionic conductors.Recently, a structure-dynamic approach [20][21][22][23][24][25] has been proposed for the development of nanoionics [26], particularly, for detailed description of processes in the region of EC/AdSIC coherent ideally polarizable heterojunctions. The approach includes a structure-dynamic model of a nanostructure, a method of -hidden‖ variables and a physico-mathematical formalism which operates these variables.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Maxwell displacement current and nature of Jonsher’s “universal” dynamic response in nanoionics

2014

Ionics

New notion -Maxwell displacement current on potential barrier -is introduced in the structuredynamic approach of nanoionics for description of collective phenomenon: coupled ion-transport and dielectric-polarization processes occurring during ionic space charge formation and relaxation in non-uniform potential relief. We simulate the processes: (i) in an electronic conductor/advanced superionic conductor (AdSIC) ideally polarizable coherent heterojunction, (ii) in a few strained monolayers of solid electrolyte (SE) located between two AdSICs forming coherent interfaces with SE. We prove the sum of ionic current over any barrier and Maxwell displacement current through the same barrier is equal to the current of current generator.-Universal‖ dynamic response, Re*()   n (n < 1), was found for frequency-dependent conductivity *() for case (ii) with an exponential distribution of potential barrier heights in SE. The nature of phenomenon is revealed. The amplitudes of non-equilibrium ion concentrations (and induced voltages) in space charge region of SE change approximately as   -1 . Amplitudes yield a main linear contribution to Re*(). The deviation from linearity is provided by the cosine of phase shift  between current and voltage in SE-space charge but cos depends relatively slightly on  (near constant loss effect) for coupled ion-transport and dielectric-polarization processes.The canonical physical-mathematical formalism for the description of ion transport in solids [1] is based on the concept of a regular crystalline potential relief, i.e. the heights  of potential barriers are const. As a consequence, ion-transport characteristics (mean-square displacement, diffusion coefficient, mobility, activation energy) have a clear physical meaning only at averaging in the scale much exceeding the length of an elementary ion jump. However, the variation of  with a space coordinate x can be considerable in objects of solid state ionics. For example, local regions with  variation about 1 eV/nm exist in disordered solid electrolytes (SE) [2][3][4] and in crystals of superionic conductors (SIC) [5]. Various degrees of ordering occur near surfaces and in the region of interphase and intercrystalline boundaries [6] where specific ion dynamics can arise on the nanoscale [7] due to a non-uniform potential relief. The interface structure exhibits itself in, e.g., frequency-capacitance characteristics of EC/SIC heterojunctions [8][9][10]. The classification of solid ionic conductors [8-10] distinguishes a class of advanced superionic conductors (AdSIC) among SE and SIC because AdSIC-crystal structure is close to optimal for fast ion transport (FIT). This crystal structure determines the record high level of iontransport characteristics. The FIT structure represents a rigid sub-lattice of immobile ions in which there are the crystallographic positions interconnected with each other by low potential barriers (conduction tunnels) for hopping mobile ions. The number of such positions is several times larger ...