A Hierarchical SnO2@Ni6MnO8 Composite for High-Capacity Lithium-Ion Batteries

Semiconductor-based composites are potential anodes for Li-ion batteries, owing to their high theoretical capacity and low cost. However, low stability induced by large volumetric change in cycling restricts the applications of such composites. Here, a hierarchical SnO2@Ni6MnO8 composite comprising Ni6MnO8 nanoflakes growing on the surface of a three-dimensional (3D) SnO2 is developed by a hydrothermal synthesis method, achieving good electrochemical performance as a Li-ion battery anode. The composite provides spaces to buffer volume expansion, its hierarchical profile benefits the fast transport of Li+ ions and electrons, and the Ni6MnO8 coating on SnO2 improves conductivity. Compared to SnO2, the Ni6MnO8 coating significantly enhances the discharge capacity and stability. The SnO2@Ni6MnO8 anode displays 1030 mAh g−1 at 0.1 A g−1 and exhibits 800 mAh g−1 under 0.5 A g−1, along with high Coulombic efficiency of 95%. Furthermore, stable rate performance can be achieved, indicating promising applications.