Template-Assisted Epitaxial Growth of Ordered SnO Nanorods Arrays with Different Hollow Structures for High-Performance Sodium Storage.

Anode materials for sodium ion batteries (SIBs) are confronted with severe volume expansion and poor electrical conductivity. Construction of assembled structures featuring hollow interior and carbon material modification is considered as an efficient strategy to address the issues. Herein, a novel template-assisted epitaxial growth method, ingeniously exploiting lattice matching nature, is developed to fabricate hollow ordered architectures assembled by SnO nanorods. SnO nanorods growing along [100] direction can achieve lattice-matched epitaxial growth on (110) plane of α-FeO. Driven by the lattice matching, different α-FeO templates possessing different crystal plane orientations enable distinct assembly modes of SnO, and four kinds of hollow ordered SnO@C nanorods arrays (HONAs) with different morphologies including disc, hexahedron, dodecahedron and tetrakaidecahedron (denoted as Di-, He-, Do-, and Te-SnO@C) are achieved. Benefiting from the synergy of hollow structure, carbon coating and ordered assembly structure, good structural integrity and stability and enhanced electrical conductivity are realized, resulting in impressive sodium storage performances when utilized as SIB anodes. Specifically, Te-SnO@C HONAs exhibit excellent rate capability (385.6 mAh·g at 2.0 A·g) and remarkable cycling stability (355.4 mAh·g after 2000 cycles at 1.0 A·g). This work provides a promising route for constructing advanced SIB anode materials through epitaxial growth for rational structural design.