TiO2 particles wrapped onto macroporous germanium skeleton as high performance anode for lithium-ion batteries

Abstract

Macroporous (MP) Ge skeleton wrapped with TiO2 particles layer is straightforwardly fabricated via one-step etching of the GeTiAl precursor alloy under mild conditions. During the selective dissolution of Al from GeTiAl alloy, Ge atoms assemble to form three dimensional (3D) network nanostructure with rich porosity. Ti atoms undergo the natural oxidation and aggregation to form TiO2 particles layer distributed on the porous Ge surface. Combined with the 3D porous architecture and robust TiO2 layer, the as-prepared Ge@TiO2 shows unique lithium storage performances with superior cycling stability and rate capability. It delivers a reversible capacity of 963 mAh g−1 after 100 cycles at 400 mA g−1. Even after cycling for 300 loops at the high rate of 3200 mA g−1, the specific capacity still remains as high as 717 mAh g−1. MP Ge@TiO2 material presents promising application potential as an alternative anode in the fields of lithium storage technologies.