Microwave-assisted and gram-scale synthesis of ultrathin SnO₂ nanosheets with enhanced lithium storage properties

The rational design and fabrication of SnO₂-based anode materials could offer a powerful way of effectively alleviating their large volume variation and guaranteeing excellent reaction kinetics for electrochemical lithium storage. Herein, we present an ultrarapid, low-cost, and simple microwave-assisted synthesis of ultrathin SnO₂ nanosheets at the gram-scale. The two-dimensional (2D) anisotropic growth depends on microwave dielectric irradiation coupled with surfactant structural direction, and is conducted under low-temperature atmospheric conditions. The ultrathin 2D nanostructure holds a great surface tin atom percentage with high activity, where the electrochemical reaction processes could be facilitated that highly dependent on the surface. Compared with 1D SnO₂ nanorods, the ultrathin SnO₂ nanosheets exhibit remarkably improved electrochemical lithium storage properties with a high reversible capacity of 757.6 mAh g^-1 at a current density of 200 mA g^-1 up to 40 cycles as well as excellent rate capability and cycling stability. Specifically, the ultrathin 2D nanosheet could significantly reduce ion diffusion paths, thus allowing faster phase transitions, while the sufficient external surface interspace and interior porous configuration could successfully accommodate the huge volume changes. Even more importantly, we develop a promising strategy to produce ultrathin SnO₂ nanosheets to tackle their intrinsic problems for commercial applications.