Amorphous Sn2P2O7 thin film electrodes have been successfully fabricated by radio frequency (r.f.) magnetron sputtering. Reversible lithiation and delithiation processes occurring at 1.47V and 2.01V versus lithium are observed in both discharge/charge curves and cyclic voltammograms of the amorphous Sn2P2O7 thin film electrodes for the first time. Large reversible capacity around 887mAhg−1 is achieved when the cell is cycled between 0.01V and 4.0V, corresponding to 9.2 Li per Sn2P2O7 unit. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) evidences, the reaction mechanism involving the reversible decomposition and regeneration of amorphous Sn2P2O7 as well as alloying and de-alloying of tin with lithium is proposed.