3D Fast Sodium Transport Network of MoS2 Endowed by Coupling of Sulfur Vacancies and Sn Doping for Outstanding Sodium Storage

Abstract

AbstractA sulfur vacancy‐rich, Sn‐doped as well as carbon‐coated MoS2 composite (Vs‐SMS@C) is rationally synthesized via a simple hydrothermal method combined with ball‐milling reduction, which enhances the sodium storage performance. Benefiting from the 3D fast Na+ transport network composed of the defective carbon coating, Mo─S─C bonds, enlarged interlayer spacing, S‐vacancies, and lattice distortion in the composite, the Na+ storage kinetics is significantly accelerated. As expected, Vs‐SMS@C releases an ultrahigh reversible capacity of 1089 mAh g−1 at 0.1 A g−1, higher than the theoretical capacity. It delivers a satisfactory capacity of 463 mAh g−1 at a high current density of 10 A g−1, which is the state‐of‐the‐art rate capability compared to other MoS2 based sodium ion battery anodes to the knowledge. Moreover, a super long‐term cycle stability is achieved by Vs‐SMS@C, which keeps 91.6% of the initial capacity after 3000 cycles under the current density of 5 A g−1 in the voltage of 0.3–3.0 V. The sodium storage mechanism of Vs‐SMS@C is investigated by employing electrochemical methods and ex situ techniques. The synergistic effect between S‐vacancies and doped‐Sn is evidenced by DFT calculations. This work opens new ideas for seeking excellent metal sulfide anodes.