Page 299 - Handbook of Battery Materials

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10
Carbons

Kimio Kinoshita

10.1
Introduction

Solid carbon materials are available in a variety of crystallographic forms, typically
classified as diamond, graphite, and amorphous carbon. More recently another
structure of carbon was identified, namely the fullerenes, whose structure resem-
bles that of a soccer ball (C 60 ). In this chapter the discussion will focus on graphites
and amorphous carbons, which are practical materials for use in aqueous batteries.
Carbonaceous materials serve several functions in electrodes and other cell com-
ponents for aqueous-electrolyte batteries, and these are summarized in Table 10.1.
Of practical importance is the contribution that is made by carbonaceous
materials as an additive to enhance the electronic conductivity of the positive
and negative electrodes. In other electrode applications, carbon serves as the
electrocatalyst for electrochemical reactions and/or the substrate on which an
electrocatalyst is located. In addition, carbonaceous materials are fabricated into
solid structures which serve as the bipolar separator or current collector. Clearly,
carbon is an important material for aqueous-electrolyte batteries. It would be
very difficult to identify a practical alternative to carbon-based materials in many
of their battery applications. The attractive features of carbon in electrochemical
applications are its high electrical conductivity, acceptable chemical stability, and
low cost. These characteristics are important for the widespread acceptance of
carbon in aqueous electrolyte batteries.

10.2
Physicochemical Properties of Carbon Materials

10.2.1
Physical Properties
The crystal structure of graphite and amorphous carbon is illustrated by the
schematic representations given in Figure 10.1.

Handbook of Battery Materials, Second Edition. Edited by Claus Daniel and J¨ urgen O. Besenhard.
 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.