Page 58 - MODERN ELECTROCHEMISTRY

ELECTROCHEMISTRY 3

heat engine driving a generator. Thus, when the NASA pioneers turned to the design
of the first space vehicles—low weight being at a premium—they chose the electro-
chemical fuel cell (which provides the same amount of energy as conventional cells
at half the weight) as the source of auxiliary power in space. These cells are used in
all U.S. space vehicles and will be likely to power the first mass produced electric
cars. 2
These few examples grew out of the chest of treasures opened up by Galvani and
by Volta. Diabetics will soon be able to check their glucose levels by glancing at a
wrist meter that measures sugar content electrochemically. Tritium, an essential
component of nuclear weaponry, may be made electrochemically at a fraction of the
cost of its production in a nuclear reactor.
Holding off dielectric breakdown in water by means of electrochemically formed
coatings can allow condenser plates to store gargantuan energies for powering the
lasers of the Star Wars weaponry. Electrochemistry can be used to consume domestic
wastes with no noxious effluents reaching the air. The North Sea oil platforms are
protected by corrosion inhibitors that slow down the electrochemical reactions that
deteriorate the metal in the rigs.
In this book, an attempt will be made to present the basis of all this new
technology, but in a way in which the first consideration is a lucid explanation. Before
we look closely at the individual parts of the territory, it is good to have a look at the
whole country from above.

1.2. TWO KINDS OF ELECTROCHEMISTRY
According to the philosophers, all science is one, but that is not how it seems in
the case of electrochemistry. The two main types do not at first seem to be strongly
connected (see Fig. 1.1). These are the physical chemistry of ionically conducting
solutions (ionics) and the physical chemistry of electrically charged interfaces (elec-
trodics).
This text discusses four aspects of ionic electrochemistry: ion–solvent interac-
tions, ion–ion interactions, ion transport in solution, and ionic liquids.
The physical chemistry of ionic solutions deals with ions and solvents and how
ions interact dynamically with water as they move about in solutions. The study of
ion–ion interactions tells us how ions associate, sometimes even forming polymers in
solution. These interactions are important for the new spectroscopic techniques,
neutron diffraction and infrared spectroscopy; and for molecular dynamics (MD).
The study of transport covers diffusion and conductance of ions in solution, where
much of the basis is phenomenological.

2
Batteries carry the active material, the reaction of which produces electricity. Fuel cells store the fuel used
to produce electricity in a fuel tank. Batteries limit the range of electric cars to ~150 miles. However,
electric cars powered by fuel cells are limited only by the size of the fuel tank.