*Article* **One-Dimensional Porous Silicon Nanowires with Large Surface Area for Fast Charge–Discharge Lithium-Ion Batteries**

**Xu Chen 1, Qinsong Bi 1, Muhammad Sajjad 1, Xu Wang 2, Yang Ren 1, Xiaowei Zhou 1,\*, Wen Xu 1,\* and Zhu Liu 1,3,\***


Received: 10 April 2018; Accepted: 25 April 2018; Published: 27 April 2018

**Abstract:** In this study, one-dimensional porous silicon nanowire (1D–PSiNW) arrays were fabricated by one-step metal-assisted chemical etching (MACE) to etch phosphorus-doped silicon wafers. The as-prepared mesoporous 1D–PSiNW arrays here had especially high specific surface areas of 323.47 <sup>m</sup>2·g<sup>−</sup><sup>1</sup> and were applied as anodes to achieve fast charge–discharge performance for lithium ion batteries (LIBs). The 1D–PSiNWs anodes with feature size of ~7 nm exhibited reversible specific capacity of 2061.1 mAh·g<sup>−</sup><sup>1</sup> after 1000 cycles at a high current density of 1.5 <sup>A</sup>·g<sup>−</sup>1. Moreover, under the ultrafast charge–discharge current rate of 16.0 <sup>A</sup>·g<sup>−</sup>1, the 1D–PSiNWs anodes still maintained 586.7 mAh·g<sup>−</sup><sup>1</sup> capacity even after 5000 cycles. This nanoporous 1D–PSiNW with high surface area is a potential anode candidate for the ultrafast charge–discharge in LIBs with high specific capacity and superior cycling performance.

**Keywords:** mesoporous structure; high surface areas; ultrafast; long-cycling life
