Amorphous tin containing composite oxides are a promising negative electrode material for rechargeable lithium batteries. We have investigated the electrochemical behaviour of several SnBxPyOz compounds vs. metallic lithium in cells containing 1 M LiClO4 dissolved in ethylenecarbonate/1,2-diethoxyethane as the electrolyte. We have determined the relationship between the composition of the active electrode material and the cycling performance. Furthermore, we examined the influence of structural changes caused by single roll quenching. We also investigated the influence of the choice of phosphorus supplying starting material.