Structure-directing agent mediated synthesis of SnS₂ coupled with Ultraphene^TM as highly stable anode material for...

Sodium-ion battery (SIB) with abundant resources has been intensively developed as the efficient energy storage device. Tin disulfide (SnS₂) is one of the attractive anode materials due to its high capacity and two-dimensional structure. Nevertheless, volume expansion and low conductivity result in the poor rate performance and stability. In this study, three strategies are applied to design efficient SnS₂-based anode materials for the SIB. Two precursor solvents of deionized water (DIW) and ethanol and one structure-directing agent of cetyltrimethylammonium bromide (CTAB) are incorporated to synthesize SnS₂. The commercial Ulraphene^TM is further mixed with SnS₂ to design composites (U/s-SnS₂) with different ratios. The optimal SnS₂ and U/s-SnS₂ anodes respectively show the specific capacities of 187.7 and 326.3 mAh/g at 1.6 A/g. After 100 cycles, the U/s-SnS₂ anode still attains specific capacities of 308.7 and 438.9 mAh/g at 1.0 and 0.1 A/g corresponding to capacity retentions of 74.5% and 80.1%, respectively. The excellent rate performance and cycling stability of the U/s-SnS₂ anode are attributed to the smaller charge-transfer resistance and the larger Na⁺ diffusion coefficient. This work successfully brings a blueprint for adopting several useful strategies to improve the electrochemical performance of SnS₂. The effects for all parameters are also carefully explained.