Multiphase Ge-based Ge/FeGe/FeGe2/C composite anode for high performance lithium ion batteries

•A multiphase Ge-based Ge/FeGe/FeGe2/C composite is prepared.•The in-situ formed intermetallic compounds is conductive and act as buffer for volume expansion.•The Ge/FeGe/FeGe2/C anodes exhibit good cycling stability and high rate capability.•The synthetic route could be extended to other kinds of multiphase Ge-based composites.

A multiphase Ge-based Ge/FeGe/FeGe2/C (Fe-Ge-C) composite is prepared through the reaction between ferrous tartrate and GeO2 at Ar/H2 atmosphere, in which the active Ge, alloying components and amorphous carbon are generated synchronically. When evaluated as an anode material for lithium ion batteries, the Fe-Ge-C anode manifests an enhanced capacity of 1095 mA h g−1 at 0.1 A g−1 and with capacity retention of 890 mA h g−1 at 0.5 A g−1 over 400 cycles. A good rate capacity of 465 mA h g−1 at 10 A g−1 is also obtained. The synchronically formed conductive alloying components and amorphous carbon lead to the long cycle stability, and good rate capability. Furthermore, the synthetic route could be extended to the preparation of other kinds of multiphase Ge-based composites.

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