The fabrication method of a lithium microbattery provides for use of a substrate successively covered by: a cathode, a solid electrolyte, and a first electrically conducting layer made from a material configured to combine with the lithium atoms. The first layer is devoid of contact with the cathode. The method further includes formation of a second electrically conducting layer configured to form a diffusion barrier for the lithium atoms. The second layer is electrically connected to the first layer and leaves at least a part of the first layer uncovered, the part being facing the electrolyte. Electrochemical deposition of a lithium anode is then performed from germination from the first and second electrically conducting layers.