Single-Step Electrochemical Liquid-Liquid-Solid-Assisted Growth of Ge-Sn Nanostructures as a Long-Life Anode Material with Boosted Areal Capacity

A single-step electrochemical liquid-liquid-solid (ec-LLS) deposition route is developed for growing nanowire-based Ge-Sn nanostructures with tailored morphologies and compositions. Composite films, submicron fibers, nanowires, and also three-dimensional (3D) hierarchical structures are fabricated in the same electrolyte, simply by varying the electrodeposition current density. COMSOL simulations indicate that the current density is able to generate sufficient Joule heating to activate the ec-LLS growth mode. A concomitant reduction of Ge and Sn ions during Sn-doped Ge nanowire growth results in the formation of multicomponent heterostructures comprising non-equilibrium GexSn1-x, pure Sn, and Sn-rich amorphous phases. The proposed deposition technique enables the fabrication of high mass loading electrodes with enhanced Li storage properties. In particular, a 3D hierarchical structure composed of 38 wt % Ge delivers a specific capacity of 938 mA h g-1 after 400 cycles, corresponding to a high areal capacity of 4.95 mA h cm-2. We believe that the present study could be considered as a low-cost procedure for the industrial fabrication of anode materials for high-performance Li-ion battery applications.Spanish MICINN funded this work under grants MAT2017-91404-EXP, RTI2018-096273-B-I00, and RTI2018-097753-B-I00 with FEDER cofunding and through the “Severo Ochoa” Programme for Centres of Excellence in R&D (CEX2019-000917-S), and a grant was provided by Iranian Ministry of Science, Research, and Technology.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe