Highly Stable and Reversible Lithium Storage in SnO2 Nanowires Surface Coated with a Uniform Hollow Shell by Atomic Layer Deposition

• Published in: Nano letters 2014-08, Vol.14 (8), p.4852-4858
• Main Authors: Guan, Cao, Wang, Xinghui, Zhang, Qing, Fan, Zhanxi, Zhang, Hua, Fan, Hong Jin
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum wires
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl502192p

SnO2 nanowires directly grown on flexible substrates can be a good electrode for a lithium ion battery. However, Sn-based (metal Sn or SnO2) anode materials always suffer from poor stability due to a large volume expansion during cycling. In this work, we utilize atomic layer deposition (ALD) to surface engineer SnO2 nanowires, resulting in a new type of hollowed SnO2-in-TiO2 wire-in-tube nanostructure. This structure has radically improved rate capability and cycling stability compared to both bare SnO2 nanowires and solid SnO2@TiO2 core–shell nanowire electrodes. Typically a relatively stable capacity of 393.3 mAh/g has been achieved after 1000 charge–discharge cycles at a current density of 400 mA/g, and 241.2 mAh/g at 3200 mA/g. It is believed that the uniform hollow TiO2 shell provides stable surface protection and the appropriate-sized gap effectively accommodates the expansion of the interior SnO2 nanowire. This ALD-enabled method should be general to many other battery anode and cathode materials, providing a new and highly reproducible and controllable technique for improving battery performance.