For the first time, sub 10nm sized intermetallic Ag4Sn particles are prepared via an aqueous synthesis route in order to improve the electrochemical performance of pure Sn nanoparticles. High-resolution transmission electron microscopy, X-ray diffraction and thermogravimetric analysis are used to investigate the morphology, crystal structure and particle surface of the as prepared Ag4Sn nanoparticles. In addition, galvanostatic cycling and cyclic voltammetry measurements are carried out to characterize the electrochemical behavior of the particles. Upon lithiation and de-lithiation a phase transformation from Ag4Sn to Ag3Sn is observed, which has not been reported so far. The intermetallic nanoparticle-based anode delivers a specific de-lithiation capacity of 460mAhg−1 for more than 150 cycles.