Excellent Li-ion storage performances of hierarchical SnO-SnO2 composite powders and SnO nanoplates prepared by one-pot spray pyrolysis

Abstract

Hierarchical-structured SnO-SnO2 composite powders and SnO nanoplates with some SnO2 nanorods are prepared by one-pot spray pyrolysis. Dicyandiamide dissolved in the spray solution plays a key role in the preparation of the hierarchical-structured SnO-SnO2 composite powder and SnO nanoplates. The hierarchical-structured SnO-SnO2 composite powders, in which the SnO nanoplates are trapped in the porous SnO2 nanosphere, are prepared by spray pyrolysis at 800 degrees C. Sufficient conversion of the porous SnO2 nanospheres to SnO at 900 degrees C results in aggregation-free SnO2 nanoplates. SnO2 nanorods with a spherical nanodroplet at the tip are formed by Ostwald ripening. The hierarchical-structured SnO-SnO2 composite powder having high structural stability during repeated lithium alloying and dealloying reactions, shows superior discharge capacities and rate performances for lithium-ion storage compared to those of the dense-structured SnO2 powders. The discharge capacities of the hierarchical-structured SnO-SnO2 composite powders, SnO nanoplates with SnO2 nanorods, and dense-structured SnO2 powders at a current density of 1 A g(-1) for the 300th cycle are 561, 504, and 416 mA h g(-1), respectively. The SnO nanoplates with SnO2 nanorods and hierarchical-structured SnO-SnO2 powders deliver high reversible discharge capacities of 433 and 379 mA h g(-1) at an extremely high current density of 10 A g(-1), respectively. (C) 2017 Elsevier B.V. All rights reserved.