Multilayered Approach for TiO₂ Hollow-Shell-Protected SnO₂ Nanorod Arrays for Superior Lithium Storage

Abstract

The ability to control the growth of materials with nanosized precision as well as a complex hollow morphology provides rationale for the study of systems comprising both characteristics. This study explores the design of TiO hollow nanotube shells deposited by atomic layer deposition (ALD) on vertically aligned SnO nanorods grown using the vapor-liquid-solid technique. The sacrificial template approach in combination with highly conformal coating advantages of ALD resulted in a highly reproducible method to create a large surface area covered by TiO-protected SnO nanorods, which are about 60-100 nm in diameter and approximately 1 μm in length. ZnO was used as a sacrificial layer to create a 30 nm gap between SnO nanorods and 10 nm of TiO shells. Chemical etching of the sacrificial layer was used to create the desired hollow nanocomposite. A coin half-cell battery has been assembled using the TiO-protected SnO nanorods as an anode electrode and lithium foil as a counter electrode and tested for lithium storage during 70 cycles of charge/discharge in a range of 0.5-2.5 V. The TiO hollow shell functioned as a good and robust enhancer for both absolute capacity and current rate capabilities of vertically aligned SnO nanorods; an improvement in cyclic stability was also observed. This advanced self-standing hollow configuration provides several unique advantages for energy storage device applications including enhanced lithiation for superior energy storage performance.

Sn Wears Super Skin: A New Design for Long Cycling Batteries

“…Two major aspects are considered to overcome these obstacles. (1) Nanoscale: scientists have made numerous attempts to stabilize the Sn alloy geometry by constructing nanostructures with nanowires, graphene, carbon composite , or hollow SnO 2 , − porous structure, metal foams, and metal alloy scaffold. , However, these particles cannot long survive because of the severe agglomeration; nevertheless, some types of carbon may limit the particle growth. , Then we need an additional layer to separate the particles. (2) Protecting layer: this thin layer must be surpassingly good at both mechanical property and conductivity.…”

Titanium dioxide thin films by atomic layer deposition: a review

“…Both sacrificial templates and intermediate layers to obtain hollow tubular structures have been utilized. A common material here used in combination with TiO 2 is SnO 2 [241,829,830]. In the case of Carvajal et al the template made of vertically aligned SnO 2 nanorods was not sacrificial [829]; on top of these nanorods two layers were deposited by ALD, first a sacrificial ZnO layer and then TiO 2 .…”

“…A common material here used in combination with TiO 2 is SnO 2 [241,829,830]. In the case of Carvajal et al the template made of vertically aligned SnO 2 nanorods was not sacrificial [829]; on top of these nanorods two layers were deposited by ALD, first a sacrificial ZnO layer and then TiO 2 . Removal of the ZnO layer then created a 30 nm gap between the active materials, SnO 2 and TiO 2 .…”

Performance of hybrid SnO2/Li2FeMn3O8 nanostructured electrode for efficient Li ion storage application

“…The furnace is allowed to cool down to room temperature naturally after it stayed constant at 510 o C for 10 minutes before the removal of the sample. The ZnO grown dur-ing this process is etched out with a 0.1 M HCl for 5 minutes, which allowed only the SnO 2 nanorods to remain on the stainless-steel plate (Carvajal et al, 2017). Field emission scanning electron microscope (FESEM) was used to confirm the growth of the SnO 2 nanorods.…”

“…Besides, SnO 2 is a semiconductor with good lithium storage properties, exhibits nontoxic and nonreactive behaviors owing to its excellent electrical conductivity. Desirable properties of SnO 2 are believed to improve the electrochemical performance of cathode materials when applied as a coating (Carvajal et al, 2017;Guan et al, 2014;Hudaya et al, 2014). Besides these advantages, SnO 2 electrodes also encounter a few issues such as (i) severe electrode pulverization and capacity fading during the cycling process as a result of 200% volume expansion, which occurs during lithiation and de-lithiation process; (ii) relatively low discharging capability due to low electrical conductivity, which reduces the electron transport; and (iii) poor Coulombic efficiency due to irreversible conversion reaction during initial lithiation process resulting in additional cathode material consumptions.…”