We present the first results of experiments on the electrochemically driven alloying and de-alloying of Au substrates with Li-ions from organic electrolytes studied by in situ X-ray diffraction employing synchrotron radiation. Au(111) single crystals, 111-textured thin Au films and nanometer-sized Au particles on highly oriented pyrolytic graphite (HOPG) have been examined using a specially designed in situ X-ray cell. Starting from single crystalline Au systems we could follow the structural degradation and pulverization under different electrochemical conditions. Reciprocal lattice space maps show the occurrence of powder-like intensity associated with different Li-Au alloy phases. The diffraction data from the bulk Au crystals are compared with the Au(111) thin films and the behavior of the Au nano-particles on HOPG. (C) 2008 Elsevier Ltd. All rights reserved.