Supported SnS₂ nanosheet array as binder-free anode for sodium ion batteries

Transition-metal sulfides have been generally identified as one of the promising anode candidates for sodium ion batteries yet still suffer from serious capacity decay. Herein, we carry out a simple and effective hydrothermal method for preparation of vertically aligned SnS₂ nanosheets grown on carbon cloth as binder-free anode for sodium ion batteries. Specifically, the self-standing anode material displays excellent electrochemical properties including high specific capacity, outstanding rate capability, and long cycle stability. The large discharge capacity of 1039.9 mA h g⁻¹ at 0.2 A g⁻¹ is achieved. Even at much high current density of 2 A g⁻¹, the reversible capacity can reach 673.4 mA h g⁻¹ after 400 cycles. Meanwhile, this anode material can also withstand various current densities ranging from 0.1 to 2 A g⁻¹ and exhibits good capacity recovery ability. Electrochemical kinetic analysis suggests that the mechanical flexibility between SnS₂ nanosheets and carbon cloth conductive substrate could well maintain the structural integrality, thus providing favorable transport kinetics for both electrons and sodium ions during repeated battery operation.