Octahedral tin dioxide nanocrystals as high capacity anode materials for Na-ion batteries

Publisher:
RSC
Publication Type:
Journal Article
Citation:
Physical Chemistry Chemical Physics, 2013, 15 pp. 12543 - 12550
Issue Date:
2013-01
Full metadata record
Files in This Item:
Filename Description Size
2012004677OK.pdf4.6 MB
Adobe PDF
Single crystalline SnO2 nanocrystals (60 nm in size) with a uniform octahedral shape were synthesised using a hydrothermal method. Their phase and morphology were characterized by XRD and FESEM observation. TEM and HRTEM analyses identified that SnO2 octahedral nanocrystals grow along the [001] direction, consisting of dominantly exposed {221} high energy facets. When applied as anode materials for Na-ion batteries, SnO2 nanocrystals exhibited high reversible sodium storage capacity and excellent cyclability (432 mA h g-1 after 100 cycles). In particular, SnO2 nanocrystals also demonstrated a good high rate performance. Ex situ TEM analysis revealed the reaction mechanism of SnO2 nanocrystals for reversible Na ion storage. It was found that Na ions first insert into SnO2 crystals at the high voltage plateau (from 3 V to 0.8 V), and that the exposed (1 × 1) tunnel-structure could facilitate the initial insertion of Na ions. Subsequently, Na ions react with SnO2 to form NaxSn alloys and Na2O in the low voltage range (from 0.8 V to 0.01 V). The superior cyclability of SnO2 nanocrystals could be mainly ascribed to the reversible NaSn alloying and de-alloying reactions. Furthermore, the reduced Na2O matrix may help retard the aggregation of tin nanocrystals, leading to an enhanced electrochemical performance.
Please use this identifier to cite or link to this item: