Wednesday, 16 May 2018: 11:20
Room 306 (Washington State Convention Center)
This presentation will describe our latest efforts in the synthesis of nanostructured Group IV semiconductor nanowires by the electrochemical liquid-liquid-solid (ec-LLS) process for preparing rechargeable battery anode materials. Briefly, we have developed a hybrid electrodeposition strategy that mimics high temperature, chemical vapor phase nanowire growth but at low temperatures with reactants dissolved in an electrolyte. The key concept is the use of a liquid metal electrode that also serves as a seed for the crystal growth of electrodeposited Group IV semiconductors. We will first show the basic generality of the ec-LLS process in terms of material, employed substrate, electrolyte composition, and applied electrochemical waveform. Then we will discuss details of battery electrode preparation by ec-LLS and the resultant cycling performance under various treatments. We will specifically show the influence of the liquid metal seed used in ec-LLS on the cycling properties of Ge nanowires and microwires for Li+ insertion/de-insertion. Electrochemical response patterns, ex-situ electron microscopy, atom probe tomography, and X-ray diffraction patterns indicate that certain metal impurities significantly extend cyclability of Ge microwires due to an 'atomic' binder effect imparted by metal impurities incurred by the ec-LLS process.