The layered oxysulfides Sr2
MO2Cu2S2 (M = Mn, Co, Ni) consist of alternating perovskite-type Sr2
MO2 layers and copper sulfide layers. We studied the electrochemical insertion of Li into these three samples. By this we were able to study the influence of the nature of the transition metal on the Li insertion process which appears to be at least partially reversible. While the Mn compound clearly shows a Cu-Li exchange reaction, the electrochemical process for the two other compounds is more complex. The lithiated materials were studied by 7Li MAS NMR.