Large-scale synthesis of hierarchical SnO spheres assisted with poly (N-isopropylacrylamide) for high lithium storage capacity

Hierarchical tin monoxide (SnO) spheres were successfully prepared by using a new facile route, i.e., a one-pot method in an aqueous solution with the assistance of a thermosensitive polymer, poly (N-isopropylacrylamide) (PNIPAM), acting as a surfactant. The synthesized SnO spheres were assembled from irregular SnO nanosheets, which have a thickness of 20 nm and are several nanometers in length, with a rough surface homogeneously decorated by SnO nanoparticles. The formation of this hierarchical structure is achieved through the cooperation of the template-directing growth and self-assembly process. The electrochemical performance of hierarchical SnO was examined as an anode material for lithium-ion batteries. The as-synthesized SnO leads to an excellent electrochemical performance as characterized by the high specific capacity (275 mAh g(-1) at 500 mA g(-1)), cycling stability (400 mAh g(-1) after 70 charge-discharge cycles at 200 mA g(-1) with 49% capacity retention), and high rate performance (119 mAh g(-1) at 1 A g(-1)). This one-step facial method may provide an attractive alternative approach to the large-scale preparation of high-purity and low-valence transition metal oxides (TMOs) anode materials.