Synthesis,Microstructure And Electrochemical Properties Of Cu_xS And FeS₂ Nanomaterials

CuxS and FeS2 were widely used as anode materials for lithium ion batteries due to their high theoretical capacity,suitable voltage platform,low cost and environmental friendliness.However,due to the shortcomings of the material itself.such as poor conductivity and easy expansion during charging and discharging,the cycle stability of the electrode is poor,and the capacity attenuation is relatively fast,which hinders its practical application.To solve these problems,the CuxS and FeS2 materials were prepared by low-temperature precursor vulcanization method.and the morphology of the materials were controlled by temperature,surfactant and other factors.And use the carbon coating to improve the electrochemical performance of the materials.In this paper,the morphology of Cu2S was controlled by adjusting the temperature and the surfactant’s type and dosage.The nanosheets and nanoparticles of Cu2S nanostructures were obtained.In order to improve the electrical conductivity of the material and reduce the agglomeration phenomenon.The Cu2S nanostructure is modified by using dopamine as a carbon source.The carbon coating improves the cycle and rate performance of the Cu2S material,which maintains a capacity of 823.3 mAh g-1 after 120 cycles at a current density of 0.1 A g-1.It is significantly higher than the capacity of the unmodified Cu2S material(534.2 mAh g-1).The CuS materials with different morphologies such as nanopartiles,hexagonal nano-plates and microspheres were prepared by three different experimental schemes.In order to improve the electrical conductivity of the material and alleviate the volume expansion of the active material,the three-dimensional network porous carbon material was used to modify the CuS nanostructure.The electrochemical properties of the modified material were significantly improved compared to the unmodified CuS material.The capacity of modified CuS nanostructure was maintained a capacity of 336.4 mAh g-1 after 55 cycles at a current density of 0.1 A g-1.The FeS2 nanostructures which have different morphologies of large particles and microspheres was synthesized by different surfactants.The FeS2 nanostructures were carbon coated with dopamine as carbon source.The results showed that the electrochemical properties of the carbon coated FeS2 material were better which capacity was maintained at 719.7 mAh g-1 after 100 cycles of 0.1 A g-1 current density.