1. NEW SOLID ELECTRLYTES BASED ON HYDROXIDES: FUNDAMENTAL and APPLIED ASPECTS

2. Mother institute
of 5 Nobelists

3. Origin of the interest in PROTON and LITHIUM properties in Hydroxides
“ANCIENT HYSTORY”
Origin of the interest in PROTON and LITHIUM properties in Hydroxides
(applied and basic)
a) electrochemically directed: proton transport
S.Stotz, C.Wagner, Die Loeslichkeit von Wasserdampf und Wasserstoff in festen Oxiden, Ber.Bunsenges.Phys.Chem.70 (6) (1966) 781
P.M.S. Stephen, A.T. Howe, Proton conductivity and phase relatuionships in solid KOH between 248 and 406C Solid State Ionics 1 (1980) 461.
Yu.M. Baikov, Electrical conductivity of solid KOH and NaOH,
Sov.Electrochem. 18 (1982) 1256.
K.-H. Haas, U. Schindewolf, The electrical conductivity of solid and molten cesium hydroxide – A contribution to Solid Proton Condutors
Ber.Bunsenges. Phys.Chem 87 (1983) 346
K.-H. Haas, U. Schindewolf, The electrical Condutivity of Solid Alkali Hydroxides J.Sol,State Chem. 54 (1985) 342.
B.Sh. Elkin, Е.К. Shalkova, Yu.M. Baikov, Diffusivity of proton and electrical conductance of NaOH and KOH solid
Inorgan. Mater. 23 (1) (1987) 81.
. b) physico-chemically directed: chemical state of proton and its effect on thermodynamical and kinetic properties of hydroxides
Yu.M. Baikov Isotopic equilibrium in a gas-crystal system near the phase-transition points Sov.Phys.JETP 51 (6) (1980) 1136.
Yu.M. Baikov, E.K. Shalkova, Isotopic Exchange Dihydrogen-Alkaline Solid Hydroxides Kinetics and Catalysiss, 21 (6) (1980) 1426
D.T. Amm, S.L. Segel, Antiferroelectric properties of alkaline hydroxides Thermochimica Acta. 95 (1985) 447.
T.J. Bastow, M.M. Elcombe, C.J. Howard, PMR Study of Hydroxide ions Solid State Comm. 59 (5) (1986) 257
c) Lithium vjbility
V.B.Ptashnik, Y.M. Baikov Selfdiffusion Li and H in solid LiOH Sov.Phys.Solids 16, 3, (1974) 961
D.M.Folstaedt, R.N.Bifeld NMR study of Li ionmotion in LiAlO and LiOH Phys.Rev.B. 16, 11 (1978) 5928

4. Middle history 1990th
On the boundary between XX and XXI centuries – 2005
B.Sh. El’kin, Solid NaOH and KOH as superionic proton conductors: conductivity and its isotope effect, Solid State Ionics 37 (1990) 139.
M. Spaeth, K.D. Kreuer, Th. Dippel, J. Maier, Proton Transport Phenomena in pure alkaline metal Hydroxides,
Solid State Ionics 97 (1997) 291.
Yu.M.Baikov, The chemical state and the mobility of hydrogen in oxide-hydroxide solids,
Solid State Ionics 97 (1997) 471

5. OUR MODERN From 2005 up to now
Yu.M. Baikov, E.I. Nikulin, V.M.Egorov, A new ionic heterostructure of the palladium-solid hydroxide proton conductor type and its electrical characteristics in the region of the phase transition in electrolyte
Tech. Phys. Lett. 32 (3) (2006)
Yu.M.Baikov, Quantum isotope effect in “hydrogen solution in palladium-hydroxide proton conductor”
Tech. Phys. Lett. 32 (10) (2006)
Yu.M. Baikov, Isotopic shift of the prrotonic heterojunction in novel palladium-hydroxide-proton-conductor heterotructures
Solid State Ionics 178 (2007) 487.
Yu.M.Baikov, V.M.Egorov, Self-Organized Microgeterogenety and High Proton Conductivity of a Solid Eutectic of Potassium and Sodium Hydroxides,
Tech. Phys. Lett 34 (6) (2008) 503
Yu.M. Baikov New heterostructures „hydrogenated metal-solid hydroxide proton conductor“ Tech.Phys. 53, 276 (2008)

6. 2009
Solid-Hydroxide Protonic Conductors: Superionic Conductivity, Phase Transition, Isotope Effect, and Self-Organized Microheterogeneity
Yu.M.Baikov, V. M.Egorov
Physics of the Solid State , 1, 33-43
Proton Transfer in Electrochemically Active “Solid-Hydroxide Proton Conductor – Hydrogeneted Metal” Heterostructures
Yu.M.Baikov
Russian Journal of Electrochemistry , 4,
New Electrochemical Cells with Membrane-Electrode-Assembly generating Protonic Heterojunctions "Inorganic Proton Conductor-Hydrogenated Metal"
Yu. Baikov
J. of Power Sources 193, (2009)

7. Compounds under study Chemical Compounds (SOLIDS!!!!!)
KOH.H2O (146oC) NaOH.H2O (62oC)
KOH.2H2O (~ 38 – 40 oC)
Eutectics (SOLIDS!!!!!)
KOH.H2O+KOH (sometimes Commercial)
KOH+NaOH

8. N E W
SUPER
P R O T O N I C S

10. Isotopic effect
of protonic
conductivity
measured by
Direct Current
on the same
sample (!!!!)
1- at% D grows
2- at% D drops
insert:
blank experiment

11. Superprotonic conduction and the significance of the self-organized microheterogeneity of the eutectics
Identification of the monohydrate KOHH2O and eutectics (KOH+KOHH2O) or (KOH+NaOH) with superprotonics is a point that does not appear to raise any question if we consider their macroscopic parameters (σ > 1 mS/cm, Eact ≤ eV). Viewed from the standpoint of the microscopic mechanism of conduction, however, the monohydrate and the eutectics should be treated separately.
Monohydrate samples are single phase although polycrystalline in texture.
Eutectics in the solid state are essentially heterogeneous mixtures of microcrystals of two chemically different compounds.

12. Important part of PHASE DIAGRAM of KOH – H2O system Eutectic mixture of KOH+KOHH2O (~1:1)
Chemical compound monohydrate
KOHH2O
Color peaks are the
DSC spectra of
studied compounds:
1. Monohydrate has
melting point
419 K only!
2. Eutectic has
melting at 373 K
and at 360 K
likely phase transition

13. Comparison of the conductivity of solid eutectic KOH+KOHH2O
as solid protonics
(>84C)
and individual
components
forming this eutectic
at the same temperature range
KOH below 150C
are semiconductors!

14. PHASE DIAGRAM of the system KOH+NaOH with EUTECTIC point at mole relation KOH:NaOH=1:1
Stars – phase transition points
of individual compounds and
“phase transition” of eutectic
Orange columns indicate the temperature interval of superprotonic conductance
of KOH, NaOH and their eutectic mixture.
Peaks were obtained by Differential Scanning Calorimetry (DSC):
Green – melting point;
Blue – “phase transition”,
likely 1st order transition.

15. Comparison of the conductivity
of solid eutectic KOH+NaOH as solid protonics (>84C)
and individual components
forming this eutectic
at the same temperature range
NaOH and KOH
below 150C
are semiconductors!

16. The universally accepted concepts of physical chemistry concerning the micro- or nanosized heterogeneity characteristic of eutectic mixtures and on its sometimes dramatic effect on the physico-chemical properties underlie also two versions of the hypothesis bearing on the origin of conductivity of the eutectic (KOH+NaOH), which appears to be radically different in nature and substantially higher than that of individual NaOH and KOH.
The first version rests on the increase of the ionic conductivity of electrolyte-containing composite materials achieved by artificially making the material microheterogeneous, a phenomenon that has become a subject of intense interest.
The second version draws from the possibility of considerably modifying the properties of NaOH and KOH micro- or nanoclusters through self-organization of eutectics. This may become manifest, in particular, in a lowering of the temperatures of solid-state phase transitions, above which high protonic conductivity is known to exist Deciding between these versions or selection of any other would require a dedicated study.

17. Electrochemical activity of eutectic solid protonic conductor KOH+NaOH
1- Voltage on Cell
2- Potential of
Protonic
Heterojunction
PdHx|OH- vs Pd
3. Power produced
by this
rechargeable
battery after
e.g. 24-hours
charging by
0.4 mA at 1.7 V.
Discharging by black arrow was stable ~15 hour.

18. Electrochemical activity of Ti(Hx)|KOHH2O|C, 370 K
(-)Ti|KOHH2O|C
Electrochemical activity of Ti(Hx)|KOHH2O|C, 370 K
Monohydrate of KOH
has proved as solid
electrolyte of some electrochemical cells.
(-)Ti|KOH.H2O|C(+)
works as battery
of e.m.f V
Response of this cell
on different type of
loading
(sign and value
of overpotential ).
Insert: details of peak of Z//

19. with KOHH2O (solid, Tm=419 K) Isotopic effect of the conductivity &
electrode processes
with KOHH2O
(solid, Tm=419 K)
measured by
IMPEDANCE
(Alternative Current)
at 369 K (96 C)
Really it was used
three-electrode
cell
PdHx|KOHH2O|C,
third electrode was Pd wire in the middle of electrolyte