Study Of Anode Material Derived ZIF-8 Material For Sodium-ion Batteries

The rapid consumption of non-renewable energy resource has increased the demand for electrochemical energy storage devices.Compared with lithium-ion batteries(LIBs),sodium-ion batteries(SIBs)have been extensively studied due to abundant sodium resources and appropriate redox potential.At present,exploring suitable anode materials is still a crucial issue for the performance improvement of SIBs.Zinc sulfide(ZnS),with higher theoretical capacity and a lower redox potential,is considered as one of the promising SIBs anode materials.However,the structure of ZnS is easy to collapse and poor conductivity,which inevitably leads to unsatisfactory sodium storage performance.In this paper,a solution-grown zeolitic imidazolate framework(ZIF-8)is used as the precursor,combined with ion exchange and electrospinning processes to design ZnS-based heterostructures and construct hollow ZnS-embedded carbon nanofibers(CNFs)based on two point.Analyzing and explaining the contribution of the heterostructure interface and carbon-coated 3D conductive network to enhance the cycle stability and rate performance of the ZnS-based anodes.(1)The ZnS@Sb2S3/C heterostructure was prepared via the process of anion exchange,cation exchange and calcination.And the influence of the melt self-assembly of Sb2S3 on the final morphology and electrochemical performance was explored.When the cation exchange time was adjusted to 5.0 h,ZnS@Sb2S3/C-5 presents a stable micro-rod structure.Due to the unique micro-nano structure and the interaction between the heterogeneous interface,the anode displayed an ultra-high capacity of 622.1 mA h g-1 at a current of 20.0 A g-1 after assembled half cells.It could still possess a high retention rate of 93.71%,after 1000 cycles of charging and discharging at 5.0 A g-1.(2)Combining the process of electrospinning,low-temperature sulfuration and pyrolysis,the CNFs coating hollow ZnS(ZnS@CNFs)self-supporting anode materials with different contents and carbonized temperatures were prepared,respectively.The effect of carbonization temperature on the morphology and sodium storage performance of the fiber membrane was also explored,and the contribution of C-S bonds to the stable cycle is analyzed at the same time.The optimized 1.5-ZnS@CNFs-800 electrodes presented outstanding rate capability and cycle stability.After matching the full battery,it shows a high energy density of 156.9 Wh kg-1.