Abstract: Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoret-ical capacity and low cost. However, the poor cyclability and inferior rate performance hinder its large-scale applications. Here, hollow silicon/germanium (H-SiGe) nanospheres with a binary-active compo-nent and heterogeneous structure combined with porous carbon (pC) reinforcing are synthesized as lithium-ion battery anodes. Experimental studies demonstrate that the H-SiGe/pC anodes possess tiny volume expansion, high ion/electron conductivity, and stable electrode interface. Theoretical calculations confirm that through the replacement of Si using Ge with rational component control, the diffusion energy barrier of lithium will be reduced and lithium storage ability can be improved because of the slight charge polarization. Benefiting from these unique merits, the H-SiGe/pC anodes display a high ini-tial specific capacity of 2922.2 mA h g^-1 at 0.1 A g^-1, superior rate capability (59.4% capacity retention from 0.5 to 8 A g^-1), and excellent cycling stability (81% retention after 700 cycles at 5 A g^-1 at 1.0-1.2 mg cm^-2). An outstanding stability is preserved even at a high loading of 3.2 mg cm^-2 with an improved reversible capacity of 429.1 mA h g^-1 after 500 cycles at 4 A g^-1. Furthermore, the full-cell with the prelithiated H-SiGe/pC anode and LiFePO₄ cathode exhibits an impressive capacity performance.

Key words: Si/Ge, Heterostructures, Anode, Molten salt, Li-ion battery