SOLID STATE ELECTROCHEMISTRY: INTRODUCTION

A BRIEF HISTORY

The origin of solid state electrochemistry was started when Michael Faraday discovered that PbF2 and Ag2S were good conductors. Michael Faraday appreciate the benefit of Unifying Science rather than compartmentalising it. However this wisdom was largely lost when the two subject of electrochemistry were developed separately, i.e solid electrochemstry and liquid electrochemistry until the recent times.

Solid state electrochemistry developed steadily up to the late 1960s. Then Warburg (1884) demosntrate that Na+ ions could be transported through glass and proposed the transference number measurement in solids.

At 1900, Nernst found the first technological application of ion transport in solids, which was called as 'Nernst Glower', a new form of electric light. When ZrO2 was doped by small amount of Y2O3, hence it emitted a bright white light on the passage of a current at high temperature. The phenomena of the Yttria doped-ZrO2 to conduct oxide ions lead to the some studies on oxide ion conductor.

At 1914, Tubandt and Lorenz found that the conductivity of solid AgI is higher just below its melting poin than that of the molten salt. This is a phenomena of insertion electrode. Meanwhile, Carl Wagner (1956) developed the theory of transport in such mixed ionic and electronic conductors.

Since the Oil Crisis on 1970, the attention focused on the development of battery and fuel cells.

References:
Bruce, P.G., 1995, Solid State Electrochemistry, Cambridge University Press, United Kingdom

SOLID ELECTROLYTE
Electrolyte is a substance that conduct electricity through the movement of ions. Figure 1 describes some devices that use a solid electrolyte.

Figure 1. Examples of solid electrolyte application

There are three types of conduction:
1. Ionic Conduction
2. Electronic Conduction
3. Mixed Conduction

Ionic conduction occurs due to migration of ions, such as in ceramic solid electrolyte. Meanwhile the electronic conduction provide by electrons migration such as in metal.

Here are the different of conductivity character between solid electrolyte and metal:
solid electrolyte:
1. conductivity range: 10^-3 S/cm - 10 S/cm
2. Ions carry the current
3. conductivity decreased exponentially as temperature decreases (activated transport)

metal:
1. conductivity range : 10 S/cm - 10^5 S/cm
2. electron carry the current
3. conductivity increase linearly as temperature decrease (phono scattering decreases as T decreases)

Figure 2 describes the ionic migration inside crystal structure of a solid electrolyte:

Thermodynamic of conduction:
The thermodynamics of ionic conduction follow Arrhenius equation, equation (1)

equation (1)