High-rate and low-temperature performance of germanium nanowires anode for lithium-ion batteries

The original version of a negative electrode of lithium-ion battery is prepared. To this end the arrays of Ge nanowires were electrodeposited from an aqueous solution onto a titanium substrate with drop-like indium crystallization centers. The nanowires were characterized by SEM, TEM, EDX, XPS, galvanostatic cycling, CV, and EIS. Electrochemical tests were carried out in a wide temperature range with using the propylene-carbonate-based electrolyte. The electrochemical performances of the nanowires were shown to be dependent on the current density upon electrodeposition. The nanowires with diameter 20 to 40 nm and length up to 0.5 μm are covered with a thin oxide layer, consisting of both stoichiometric and non-stoichiometric germanium oxides. The electrodes demonstrate excellent features, namely room-temperature specific capacity ca. 1300 mAh g−1 at 1C and 4C rate, and about 850 mAh g−1 at 24C, as well as good low-temperature performance, 255 mAh g−1 at −50 °C.