Fabrication of hierarchically branched SnO 2 nanowires by two-step deposition method and their applications to electrocatalyst support and Li ion electrode Sang Ho Lee a , Yong-Ryun Jo b , Yuseong Noh c , Bong-Joong Kim b , Won Bae Kim c, * a Department of Materials, University of Oxford, Oxford, OX1 3PH, United Kingdom b School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea c Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, South Korea highlights graphical abstract  Hierarchically branched SnO 2 nano- wires are proposed as new electrode platforms.  Superior performances exhibited in applied energy conversion and stor- age systems.  Structural advantages of the branched electrode led to the improved performances. article info Article history: Received 5 July 2017 Received in revised form 31 August 2017 Accepted 12 September 2017 Keywords: Hierarchical nanowires SnO 2 Multistep-catalyzed growth Lithium-ion storage Alcohol electrooxidation abstract This paper reports hierarchically branched structures of tin dioxide nanowires for use in electrochemical energy conversion and storage electrode systems. The shallow tin dioxide branches are epitaxially grown on the tin dioxide nanowire backbones that are directly formed on current collectors. The branched tin dioxide nanowires are applied as anode electrodes for lithium-ion batteries, while palladium- incorporated branched nanowires are utilized as electrocatalysts for ethanol electrooxidation re- actions. The structural benefits of these hierarchical platforms, such as enlarged electrochemical active surface area, void space formed between the branched structures, and conformal contact of the elec- troactive materials with current collectors, play important roles in improving the electrochemical Li-ion storage as well as electrocatalytic activity. © 2017 Elsevier B.V. All rights reserved. 1. Introduction In the decades, great scientific attention has been focused on the development of green and sustainable power sources to overcome the global energy crisis that is attributed to fossil fuel exhaustion and increased energy consumption. Amongst a wide range of power systems, fuel cells and rechargeable batteries have been ranked as one of the most promising energy sources for the next-generation device because they can be environmentally-friendly applied in diverse fields from compact electronics and electric vehicles throughout large-scale grid systems [1e3]. The fundamental prop- erties of these electrochemical devices are strongly dependent on * Corresponding author. E-mail address: kimwb@postech.ac.kr (W.B. Kim). Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour http://dx.doi.org/10.1016/j.jpowsour.2017.09.045 0378-7753/© 2017 Elsevier B.V. All rights reserved. Journal of Power Sources 367 (2017) 1e7