The low capacity of traditional graphite (372 mAh g−1) greatly limits its development as electrode material for future applications, and seeking new anode material is becoming extremely urgent in order to meet the increasing demands. In this work, flexible, self-supporting CuGa2 films are fabricated by simply painting liquid Ga onto commercial Cu films, which can be used as electrodes directly after annealing. When the CuGa2 films are applied as anodes in lithium ion batteries, higher capacity (more than 630 mAh g−1 at a current density of 200 mA g−1) and better rate performance (463.7 mAh g−1 at 4000 mA g−1) are achieved compared with those with pure Ga electrodes. Meanwhile, the lithiation-delithiation mechanism is detected by in-situ X-ray diffraction, and the alloying-dealloying processes (CuGa2 + 2xLi+ + 2xe− ↔ Cu + 2Li x Ga) can be verified at the first and fourth cycles.