Easy preparation of nanoporous Ge/CuGe composite and its high performances towards lithium storage.

Nanoporous Ge/CuGe composite is fabricated simply through selective dealloying of GeCuAl precursor alloy in dilute alkaline solution. The as-made Ge/CuGe is characterized by three dimensional (3D) bicontinuous network nanostructure which comprises of substantial nanoscale pore voids and ligaments. Owing to the 3D porous architecture and the introduction of well-conductive CuGe, the lithium storage performances of Ge are dramatically enhanced in terms of higher cycling stability and superior rate performance. Nanoporous Ge/CuGe anode delivers steady capacities above 1000 mA h g upon cycling for 70 loops at 400 mA g. In particular, after 300 cycles at the high rate of 3200 mA g the capacity retention for Ge/CuGe is able to reach a maximum of 99.3%. On the contrary, the pure nanoporous Ge encounters severe capacity decay. In view of the outstanding energy storage performances and easy preparation, nanoporous Ge/CuGe exhibits great application potential as an advanced anode in lithium storage related technologies.