Tin Oxide Nanowires As High Energy Density Anodes for Lithium-Ion Batteries
The tin nanocluster covered tin oxide nanowires show an exceptional capacity of 814 mAhg-1 even after 100 cycles at a high current density of 100 mA/g . Recently, thin protective coatings are of great interest for enhancing the durability. Here, we demonstrate that such a thin layer of protective coating of titania or alumina using atomic layer deposition technique could stabilize and improve cyclability. Figure 1b shows a 5 nm titania layer coated on tin oxide nanowires. Without coating, tin oxide nanowires exhibited a very low capacity of 300 mAhg-1. With a 5 nm titania layer, the capacity retention increased to 767 and 664 mAhg-1(Figure 1c) at the current density of 700 and 1500 mA/g after 30 cycles, respectively . The protective coatings also reduced the irreversible capacity losses associated with SEI formation.
Figure 1: a) SEM image of SnO2 NWs using Solvo-plasma synthesis, b) TEM image showing a thin layer of titania on tin oxide nanowires, c) the capacity retention at different current densities compared with non-coating tin oxide nanowires
 Nguyen et al., manuscript in preparation
 P. Meduri, C. Pendyala, V. Kumar, G. U. Sumanasekera, M. K. Sunkara, Nano lett. 2009, 9, 612.