Sulfur-Deficient Porous SnS_2-x Microflowers as Superior Anode for Alkaline Ion Batteries

SnS₂ as a high energy anode material has attracted extensive research interest recently. However, the fast capacity decay and low rate performance in alkaline-ion batteries associated with repeated volume variation and low electrical conductivity plague them from practical application. Herein, we propose a facile method to solve this problem by synthesizing porous SnS₂ microflowers with in-situ formed sulfur vacancies. The flexible porous nanosheets in the three-dimensional flower-like nanostructure provide facile strain relaxation to avoid stress concentration during the volume changes. Rich sulfur vacancies and porous structure enable the fast and efficient electron transport. The porous SnS_2-x microflowers exhibit outstanding performance for lithium ion battery in terms of high capacity (1375 mAh g^-1 at 100 mA g^-1) and outstanding rate capability (827 mA h g^-1 at high rate of 2 A g^-1). For sodium ion battery, a high capacity (~522 mAh g^-1) can be achieved at 5 A g^-1 after 200 cycles for SnS_2-x microflowers. The rational design in nanostructures, as well as the chemical compositions, might create new opportunities in designing the new architecture for highly efficient energy storage devices.