For a century, nickel-cadmium (Ni-Cd) batteries have been widely used as electrochemical energy-storage cells. However, due to the rapid development of portable electronic devices and the increasing search for cleaner electric vehicles, new generations of batteries have been investigated during the last few decades. Among them, nickel metal hydride (Ni-MH) batteries, with their larger capacities and improved environmental compatibility, have shown their ability to replace Ni-Cd cells. The negative electrodes of Ni-MH batteries are made of reversibly hydride-forming intermetallic compounds. In this article, the crystallographic and thermodynamic properties of these compounds will be reviewed. Their hydrogen-absorption properties, their electrochemical performance, and the solutions that have been found to achieve reliable cycle life will be presented. The industrial market for Ni-MH batteries will also be discussed in comparison with other battery systems.
Jean-Marc Joubert began work in the Laboratoire de Chimie Métallurgique des Terres Rares in Thiais, France, in 1996, working toward his PhD degree in the field of metal hydride systems. He earned his physics engineer diploma in 1992 from the Institut National des Sciences Appliquées in Rennes. After postdoctoral work in the Laboratoire de Cristallographie in Geneva, he was appointed to a permanent position in the Laboratoire de Chimie Métallurgique des Terres Rares.
Joubert can be reached by e-mail at email@example.com.
Michel Latroche is the director of research at the Laboratoire de Chimie Métallurgique des Terres Rares in Thiais, France. He studied at Nantes University and obtained his PhD degree at the Institut des Matériaux de Nantes, working on solid-state chemistry and materials science. His postdoctoral work was done at Northwestern University in the Chemistry Department. He then returned to France to work in the metal hydride field at CNRS.
Latroche can be reached by e-mail at firstname.lastname@example.org.
Annick Percheron-Guégan is the director of research at the Centre National de la Reserche Scientifique (CNRS) and head of the Laboratoire de Chimie Métallurgique des Terres Rares in Thiais, France, a position she has held since 1993. She has worked in the field of reversible metal hydrides since 1975, specifically developing Ni-MH battery applications. She obtained her engineer diploma from the Ecole Nationale de Chimie de Bordeaux in 1963 and prepared her PhD thesis at the Laboratoire des Terres Rares, defending it in 1970 at Orsay University.
Percheron-Guégan can be reached by e-mail at email@example.com.