Silver: high performance anode for thin film lithium ion batteries

Among metals and intermetallic compounds, silver exhibits a high specific capacity according to the formation of different Ag–Li alloys (up to AgLi12) in a very low voltage range versus lithium (0.250–0 V). Electrochemical results including Galvanostatic Intermittent Titration Technique (GITT) as well as cycling behaviour experiments confirmed the interesting characteristics of silver thin film electrodes prepared by radio frequency (r.f.) sputtering. XRD patterns recorded at different electrochemical stages of the alloying/de-alloying processes showed the complexity of the silver–lithium system under dynamic conditions. Cycling life depends on several parameters and particularly of the careful choice of cut-off voltages. In very well monitored conditions, galvanostatic cycles exhibited flat reversible plateaus with a minimal voltage value (0.050 V) between charge and discharge, a feature of great interest in the use of an electrode. The first results of a lithium ion battery with both silver and LiMn1.5Ni0.5O4 thin films are presented.