SOLIDIONIC

The search for and development of electrochemical cells with new electrolytes or new electrode–electrolyte assemblies  is based on fundamental investigations of the electrochemical activity of materials. This poster present a search, the novelty of which is determined by the previously unknown combination of well-known materials as membrane–electrode assembly. These are a solid electrolyte based on potassium hydroxide monohydrate and a negative semiconducting electrode (germanium).  We have prepared  electrochemically  active cells of the formula(–)Ge|KOH⋅nH2O|C(+). Ge-electrode was the thin plate of  p-Ge( 28 Ω.cm).

The solid electrolyte (KOH monohydrate) studied by us  since 2007[1,2].  As the member of  а family of water–potassium hydroxide system it is well and long known in the physical chemistry. Our interest was devoted to KOH ⋅ nH2O solid hydrates with n = 0.5, 1.0,  2.0. Graphite (C) is well known as a multifunctional electrode .   Recently, it has been shown [2] that silicon exhibitsi in heterostructures with solid potassium hydroxide mono- and dihydrate  electrochemical  activity,  the  character  of which depends on the doping level. It was naturally of interest to expand the group of previously studied electrode materials (C, Si, and Sn) in contact with solid hydroxide proton  conductors by including another group-IV element  Ge.  On three figures electrochemical data by different types are shown. Top left are cyclic voltamograms at different ranges of cell voltage and rates.  The middle picture allows to evaluate the exchange currents in a cell. On the bottom figure EIS  are shown at  some overpotential relatively  e.m.f.=0.7 V.
References
[1]Yu.M. Baikov, Solid State Ionic  208 (2012) 17.
[2] http://www.solidionic.com

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UNUSUAL CELL: (-)Ge-KOH.H2O – C(+)

Senior scientist of Ioffe Institute, St-Petersburg, RF baikov.solid@gmail.com http://www.solidionic.com

The pioneering investigation of the electrochemical activity of certain ionic heterostructures with solid electrolyte KOH·2H2O (Tmelt=315 K) is due to basic and applied interest in. The special study of different chemical elements of IV group (C, Si, Sn, Pb) as electrodes of electrochemical cells with hydroxide superprotonic conductor as electrolyte has been performed. EMF (1,2 – 1,3
V) and exchange currents (0,1-1 mA/cm2) of ‘C | KOH·2H2O | TiFe’ and ‘C | KOH·2H2O |
Sn’ have been shown to be adequate to work as low-power sources for electronic devices. They are factually batteries from cheap materials without any catalysts. The scientific justification of the opportunity to use such combinations in electrochemical devices has been based on the study of physical nature of different types of heterojunctions. The isotopic shift of the electromotive forces and isotopic (HD) exchange between TiFeHx – electrodes and KOH·2H2O- electrolytes have been studied specially to prove the formation of protonic heterojunction in the electrochemical cell ‘C | KOH·2H2O | TiFe’. The metal-protonic heterojunction for
‘C | KOH·2H2O | Sn’ characterized by enough high exchange current has been studied firstly.
The semiconductor-protonic heterojunction in the heterostructure ‘C | KOH·2H2O | Si’ could be considered as the opportunity of the harmonical combination of small-sized electronic devices with batteries like studied here.
Key words: low-power battery, protonic conductor, graphite, stannum, silicon
References
1. Yu.M. Baikov, J.Power Sources, 193 (2009) 1Sp 371.
2. Yu.M. Baikov, Solid State Ionics 181 (2010) 545.
3. Yu.M.Baikov, Rus. J. Electrochemistry 48 (2012) 360.
4.. Yu.M. Baikov, Solid State Ionic 208 (2012) 17.

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Advanced Solid Electrolytes: Crystalline Hydrates and-or Eutectics of Alkaline Hydroxides