Germanium decorated on three dimensional graphene networks as binder-free anode for Li-ion batteries

Abstract

Three-dimensional (3D) graphene networks are successfully fabricated on nickel (Ni) foam by the chemical vapor deposition (CVD) technique. Amorphous Ge layer is then deposited on the 3D graphene supporting skeleton via the facile radio frequency magnetron sputtering (RFMS) method. The Ge decorated on the 3D graphene (3D Ge@Gr) networks deliver improved electrochemical performance when employed as anode for lithium ion batteries (LIBs), which is obvious superior than the two dimensional Ge nanoelectrode directly coated on the bare Ni foam (2D Ge). Significantly enhanced electrochemical cyclability upon 1500 long-term cycles under the higher current density of 1.2 mA cm−2 is accomplished in the optimized 3D Ge@Gr hybrid electrode. The interconnected 3D graphene with enlarge surface area can not only effectively provide enough space to buffer the volume change of the Ge anode during cycling, but also bring improved electrical/ionic conductivity to promote the electrochemical kinetics, thus eventually bring superb stable cyclability.