Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour Interpenetrated 3D porous silicon as high stable anode material for Li-Ion battery Yanxia Liu a,b,1 , Lijuan Qin a,1 , Fan Liu a , Yameng Fan a , Jingjing Ruan a , Suojiang Zhang a,b,∗ a Zhengzhou Key Laboratory of Energy Storage Science and Technology, Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, 45000, China b Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China HIGHLIGHTS • A template-free method is utilized to fabricate interpenetrated porous si- licon. • The porous silicon demonstrates good cycling stability and rate capability. • Detailed electrochemical measure- ments and analysis are also conducted. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Silicon-based anode Template-free method Composite gel Magnesiothermic reduction Bi-continues structure Lithium-ion batteries ABSTRACT Confronting issues of silicon-based anode for its huge volume change (∼320%), porous silicon attracts note- worthy attention. Most previous studies are concentrated on designing various sacrificial templates to endow silicon with marvelous shapes or structures. Herein, without the assistance of sacrificial template, a template-free method is developed to fabricate interpenetrated three-dimensional porous silicon. A silica composite gel, which possesses numerous nano-pores, is primarily constructed, and the silicon can be inherently equipped with these nano-pores via modified magnesiothermic reduction. Scanning electron microscope and transmission electron microscope images illustrate that the as-prepared porous silicon possesses bi-continuous structure. It also ex- hibits high initial reversible capacity (∼1.41 mAh cm −2 at 0.16 mA cm −2 ), superior cycling stability (∼0.98 mAh cm −2 after 200 cycles), and good rate performance. In addition, analysis of cyclic voltammetry curves and electrochemical impedance spectroscopy demonstrate that this porous silicon possesses appropriate channels for rapid Li + transport and low electrochemical reaction polarization resistance. 1. Introduction To meet escalating requirements of large-scale electrochemical en- ergy storage devices, Li-ion battery (LIB), especially with high energy density and power density, is urgently demanded [1,2]. Off-the-shelf LIB, composed of LiFePO 4 or LiNi x Mn y Co 1-x-y as the cathode and gra- phite as the anode, cannot satisfy various needs in energy-related ap- plications. Meanwhile, commercial carbon anode materials have ap- proached their limitation of theoretical capacity (372 mAh g −1 ). Therefore, during the past decades, many researchers have dedicated to https://doi.org/10.1016/j.jpowsour.2018.10.028 Received 25 July 2018; Received in revised form 11 September 2018; Accepted 9 October 2018 ∗ Corresponding author. Zhengzhou Key Laboratory of Energy Storage Science and Technology, Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, 45000, China. 1 These authors contributed equally to this work. E-mail address: sjzhang@ipe.ac.cn (S. Zhang). Journal of Power Sources 406 (2018) 167–175 0378-7753/ © 2018 Elsevier B.V. All rights reserved. T