Binder-free ultrathin SnS2 with superior reversibility of conversion reaction for high-rate lithium ion batteries

Highlights: • The novel thin film preparation technology through magnetron sputtering. • The unique binder-free ultrathin structure greatly improved the utilization ratio of active materials. • the binder-free SnS₂ electrode presents superior reversibility of conversion reaction. • The nanosized SnS₂ electrode exhibits high-rate performance because of the dominated pseudocapacitive effect. -- Abstract: To enhance the utilization of active materials and transform the traditional electrode preparation technology, a binder-free ultrathin SnS₂ anode for lithium ion batteries is fabricated through a simple magnetron sputtering method. In comparison with the electrode synthesized by solvothermal method and coating process, the binder-free SnS₂ electrode presents superior reversibility of conversion reaction due to the shorter ions and electrons transport path and the close contact of the active material with the electrolyte, suggesting a restraining effect on the tin agglomeration, then stabilize the electrode structure, it retains the superior capacity retention of 80% after 200 cycles at 0.5 Ag⁻¹ and the high rate capability of 788 mAh g⁻¹ at 5.0 Ag⁻¹. The ultratiny SnS₂ nanoparticles uniformly arrayed on the substrate and occurred dominant pseudocapacitive effect, guaranteeing its high-rate performance with 967 mAh g⁻¹ at 1.0 Ag⁻¹ after 200 cycles. The stable electrode morphology after cycling demonstrates its prospect for lithium ion batteries anode.