Recent progress in the development of solid electrolyte batteries

Abstract

Solid electrolyte batteries may be loosely defined as power sources within which the transfer of the ionic species between the cathode and anode plates occurs by migration through a as opposed to a liquid phase. Within this definition one may include those systems which have, for example, a gaseous depolarizer and which can not therefore be classified in the strictest sense as all-solid batteries. Again, it should be pointed out that the use of the term solid does not imply that such systems may be thought of as dry. Indeed, there is a considerable volume of evidence, which will be mentioned later, to indicate that no electrolyte system which has been developed to date can operate without the presence of a trace liquid phase. In spite of these limitations, however, electrolyte systems have a number of quite unique advantages which can not be as readily fulfilled by present day state of the art liquid electrolyte units. For example, such systems can be assembled into extremely rugged configurations and may thus be used in applications which require a battery that will withstand acceleration forces of the order of several thousand times that due to gravity coupled with spin rates of several hundred revolutions per second. Further, with liquid electrolyte batteries one is limited to that range of temperatures between which the electrolyte freezes and boils and also with loss of the electrolyte on long term standby processes of evaporation and leakage. To a large extent such problems may be avoided by the use of electrolytes though for those systems which utilize a gaseous depolarizer one also encounters problems associated with the sealing of the unit. Perhaps the most the use of a miniature batteries important advantage associated with electrolyte is the ease with which may be produced. As a general statement it is true to say that the power requirements of electronic devices are continually being reduced by the development of more sophisticated micro-electronic circuit components and hence if the advances made in these areas are to be utilized to the fullest extent there must be a corresponding reduction in the size of the power source. With the present day liquid electrolyte systems, however, the problem of containment of the liquid phase constitutes an increasingly greater problem