The effect of growth temperature on the process of insertion/extraction of sodium into germanium nanowires formed by electrodeposition using indium nanoparticles

•GeNWs were prepared by electrodeposition from aqueous solution.•Ge(OH)x/GeOx plays an important role in the Na insertion/extraction process.•GeNWs demonstrated specific capacity ca. 400 mAh/g. In the present work negative electrodes for sodium-ion batteries, containing the arrays of germanium nanowires are prepared by electrodeposition from aqueous solution at different temperatures. Germanium nanowires have been deposited on titanium substrates with indium nanoparticles, which played the role of crystallization centers for germanium. The morphology and electrochemical performances of the nanowires are shown to be dependent on solution temperatures. It has been revealed that the presence of core–shell structure of the germanium nanowires (the presence of which is determined by the solution temperature) plays an important role in the Na insertion/extraction processes into Ge nanowires.