Layered GeP-black P(Ge2P3): An advanced binary-phase anode for Li/Na-storage

Various P-Ge compounds including GeP5 and GeP3 can be easily synthesized by a direct ball milling method while GeP can not. Herein, we successfully synthesize binary-phase Ge2P3 composite which derived from layered GeP and black P. When applied as anodes for Li-ion batteries, the as-synthesized binary-phase composite delivers a large reversible capacity of 1605 mA h g(-1) with a high initial Coulombic efficiency of 89%, retains 1380 mA h g(-1) after 100 cycles and even achieves 920 mA h g(-1) at a current density of at 5 A g(-1). Also, for sodium-storage it shows a reversible capacity of 970 mA h g(-1) with an initial Coulombic efficiency of 88% and retains 890 mA h g(-1) after 100 cycles. The performance can be attributed to the following merits: the binary Li/Na-storage components host more Li/Na ions, the layered structure favors Li/Na-ion transportation and the abundant heterointerfaces increase the amount of active sites.