Page 249 - Handbook of Battery Materials

219

8
Metallic Negatives

Leo Binder

8.1
Introduction

Although many different methods of representing primary and secondary (or
storage) batteries are used, the correct form of displaying a battery system is the
following:
(−) Anode material/Electrolyte/Cathode material (+).
Therefore, being the negative electrode in the system, the anodes are frequently
called ‘negatives.’ When the battery is ready for use (discharge) the typical battery
anode consists of a metal in the form of either sheet, powder, or an electrolytic
deposit. The last version is usually found in some of the secondary (storage)
batteries. During discharge, the metal atoms are oxidized to metal ions, delivering
a number of electrons corresponding to the positive charge of the cation:
M → M n+ + ne − (8.1)

The electrons sustain the current via external load and are used to reduce the active
material of the cathode (positive). In the case of storage batteries, the ideal anodic
and cathodic reactions are completely reversible.

8.2
Overview

Since there are numerous metals used as anodes (negatives) in a variety of battery
systems with aqueous electrolytes, there are different ways of arranging them
in groups to enable easier access to the required information. Useful selection
categories may be:

1) the chemical elements (iron, zinc, lead, etc., ...)
2) battery types (primary, storage, etc., .. .)
3) methods of anode preparation (metal, metal oxide, or hydroxide + subsequent
reduction, other metal compounds + reduction, etc., ...).

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.