A first approach to a monolithic all solid state inorganic lithium battery

Despite lots of advantages of polymer batteries such as ease of manufacturing, flexibility and a large variety of possible shapes, improvements of chemical stability between the electrodes and the electrolyte seemed still to be warranted. Therefore we investigated the feasibility of a monolithic, fully inorganic solid state lithium battery. The main requirements for such an inorganic battery are a ceramic lithium electrolyte with high ionic conductivity and a large stability window, and a second ion conductor which acts as sintering additive within the whole battery to prevent high preparation temperatures which may cause undesired thermodynamic reactions between the electrodes and the electrolyte prior to the first charge of the battery. This sintering additive must at no time react with the positive lithium transition metal oxide electrode where the oxidation state of the transition metal may easily change. For these reasons, the reproducibility of the high reported ionic conductivity of Li1.3Al0.3Ti1.7(PO4)3 and the lithium-rich and lithium-poor stability limits have been investigated. For sintering additive 0.44 LiBO2·0.56 LiF has been tested. First cycling results on the system Li4Ti5O12|Li1.3Al0.3Ti1.7(PO4)3|LiMn2O4 are presented.