Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries

Abstract

Due to its high theoretical specific capacity, a silicon anode is one of the candidates for realizing high energy density lithium-ion batteries (LIBs). However, problems related to bulk silicon (e.g., low intrinsic conductivity and massive volume expansion) limit the performance of silicon anodes. In this work, to improve the performance of silicon anodes, a vertically aligned n-type silicon nanowire array (n-SiNW) was fabricated using a well-controlled, top-down nano-machining technique by combining photolithography and inductively coupled plasma reactive ion etching (ICP-RIE) at a cryogenic temperature. The array of nanowires ~1 µm in diameter and with the aspect ratio of ~10 was successfully prepared from commercial n-type silicon wafer. The half-cell LIB with free-standing n-SiNW electrode exhibited an initial Coulombic efficiency of 91.1%, which was higher than the battery with a blank n-silicon wafer electrode (i.e., 67.5%). Upon 100 cycles of stability testing at 0.06 mA cm−2, the battery with the n-SiNW electrode retained 85.9% of its 0.50 mAh cm−2 capacity after the pre-lithiation step, whereas its counterpart, the blank n-silicon wafer electrode, only maintained 61.4% of 0.21 mAh cm−2 capacity. Furthermore, 76.7% capacity retention can be obtained at a current density of 0.2 mA cm−2, showing the potential of n-SiNW anodes for high current density applications. This work presents an alternative method for facile, high precision, and high throughput patterning on a wafer-scale to obtain a high aspect ratio n-SiNW, and its application in LIBs.

Miniaturized lithium-ion batteries for on-chip energy storage

“…To solve these problems, great efforts were taken into developing advanced microelectrode manufacturing methods. 54 Several deposition technologies, including physical vapor deposition (PVD), 55 pulsed laser deposition (PLD), 56 chemistry vapor deposition (CVD), 57 and atomic layer deposition (ALD), [57][58][59] have been adopted to fabricate micro-LIBs with laminated thin film structure. Among them, ALD is an effective method to manufacture high quality thin-film electrodes.…”

Properties of silicon-based lithium batteries with different electrode nanostructures

“…1c that the silicon nanowires boast coulombic efficiency as high as 99.5% during 100 cycles of charge and discharge at 0.06mAꞏcm-2 and discharge capacity retaining 85.9% after the first cycle after pre-lithiation process. [6] The fabricating process is shown in Fig. 1a First they employ photolithography to create a photoresist thin film on silicon substrate(Fig.…”

“…Figure1. The (a) fabrication process (b) morphology (c) cycle performance coulombic of vertical silicon nanowires fabricated by RIE-ICP (d) silicon nanowires fabricated with different mask materials [6][7]. RIE-ICP is a novel method used to fabricate vertically arrayed silicon nanowires.…”

“…[5] Nugroho, A.P. and his group combine photolithography with RIE-ICP to fabricate vertical n-type silicon nanowires with great cycle performance and high coulombic efficiency, which is clearly shown in Fig.1cthat the silicon nanowires boast coulombic efficiency as high as 99.5% during 100 cycles of charge and discharge at 0.06mAꞏcm-2 and discharge capacity retaining 85.9% after the first cycle after pre-lithiation process [6]. The fabricating process is shown in Fig.1aFirst they employ photolithography to create a photoresist thin film on silicon substrate(Fig.1a) and after exposure to ultraviolate light, a circular pattern array is applied to the photoresist so that a developer solution can divest the silicon substrate of exposed photoresist selectively, leaving only circular pattern arrayed parts.…”

A critical review of silicon nanowire electrodes and their energy storage capacities in Li-ion cells

“…There are several publications reporting the performances of SiNW electrodes, [26][27][28] and notably, two review articles. 29,30 However, the reviews simply summarized the forms of SiNW electrodes and their electrochemical performances, without a critical assessment of the data.…”