Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control

Abstract

Although the performance of lithium ion-batteries continues to improve, their energy density and cycle life remain insufficient for applications in consumer electronics, transport and large-scale renewable energy storage. Silicon has a large charge storage capacity and this makes it an attractive anode material, but pulverization during cycling and an unstable solid-electrolyte interphase has limited the cycle life of silicon anodes to hundreds of cycles. Here, we show that anodes consisting of an active silicon nanotube surrounded by an ion-permeable silicon oxide shell can cycle over 6,000 times in half cells while retaining more than 85% of their initial capacity. The outer surface of the silicon nanotube is prevented from expansion by the oxide shell, and the expanding inner surface is not exposed to the electrolyte, resulting in a stable solid-electrolyte interphase. Batteries containing these double-walled silicon nanotube anodes exhibit charge capacities approximately eight times larger than conventional carbon anodes and charging rates of up to 20C (a rate of 1C corresponds to complete charge or discharge in one hour).

Microstructural evolution induced by micro-cracking during fast lithiation of single-crystalline silicon

“…2, in which only an amorphous Li x Si phase was observed. Thus, we believe that the Li 15 Si 4 phase is amorphized during the TEM sample preparation process as a result of gallium ion bombardment [24,40]. In contrast, the XRD pattern for the {110} silicon wafer shows a very weak peak at 23° suggesting the presence of a very small amount of crystalline Li 15 Si 4 , and broad peak around 43°.…”

“…If we compare the XRD data obtained before and after lithiation, broad peaks for amorphous Li x Si phase can be seen around 22°~28° and 38°~45° in both {100} and {110} silicon wafer. However, the crystalline Li 15 Si 4 phase in the {100} silicon wafers seems more prevalent. Consequently, we believe that crystallization of the lithiated silicon in the {100} electrode contributes to the generation of micro-cracks.…”

“…Under constraint, this expansion can generate stresses, leading to fracture and pulverization of the electrode, degrading the capacity of the electrode during cycling. To prevent this mechanical degradation, nanostructures such as nanowires, thin films, hollow nanoparticles and 3D porous nanoparticles are being investigated [15][16][17][18][19][20][21].…”

Towards High‐Safe Lithium Metal Anodes: Suppressing Lithium Dendrites via Tuning Surface Energy

“…Copyright 2011, Nature Publishing Group. Wu, double‐walled silicon nanotube, Reproduced with permission 59. Copyright 2012, Nature Publishing Group.…”

Variation of stress with charging rate due to strain-rate sensitivity of silicon electrodes of Li-ion batteries

“…Fracture of the electrode leads to loss of active material and creates more surface area for solid-electrolyte interphase (SEI) growth, both of which significantly contribute to the fading of the capacity of the system [2][3][4][5]. Fortunately, this mechanical damage can be mitigated by nanostructuring the silicon anodes, as has been successfully demonstrated in nanowires [6,7], thin films [8][9][10][11][12], nanoporous structures [13,14], and hollow nanoparticles [15,16]. Specifically, recent experiments and theories indicate that one can prevent fracture by taking advantage of lithiation-induced plasticity [11,[17][18][19][20][21][22].…”