Solid-state microbatteries for electronics in the 21st century

A solid-state battery is an energy converter transforming chemical into electrical energy by means of internal electron exchange. The electron transfer is mediated by mobile ions released from an ion source, the anode, and neutralised in the electron exchanger, the cathode. The positive ion is transmitted through a fast ion conductor which is a good electronic insulator, the separator. The ideal solid-state battery should be based on one unique material in which three regions corresponding to the ion source, the separator and the electron exchanger an separated by internal homojunctions. Possibilities to create homojunctions by doping and to build particular microstructures to increase the cathode efficiency are discussed. Suggestions for optimisation of cathode microstructures are presented. (C) 2000 Elsevier Science B.V. All rights reserved.