Study On Preparation Of Metal Sulfide/carbon Fiber Composites By Electrospinning And Lithium Storage Performance

Due to their remarkable benefits,such as high energy density,outstanding cycle stability,low self-discharge rate,no memory effect and eco-friendliness,lithium-ion batteries（LIBs）are now the primary power source for a variety of portable electronic devices,and new environmentally friendly vehicles.Various researchers have created high theoretical capacity anode materials to replace traditional graphite anodes in order to meet the ever-increasingly stringent application requirements.Zinc sulfide（ZnS）is considered a good candidate for novel anode materials for lithium-ion batteries due to its high theoretical capacity(962.0 m Ah g^-1),excellent natural abundance,and uncomplicated manufacturing technique.In this paper,ZnS/carbon fiber composites（ZnS/CFs）are prepared using the electrospinning method,and the lithium storage performance of ZnS/carbon fiber composites is gradually enhanced by improving the pore structure of the composite materials and adjusting the composition of transition metal sulfides in the composite materials.Using electrospinning technology,polyacrylonitrile as the electrospinning matrix material,dimethylformamide and N-methylpyrrolidone as mixed solvents,and zinc diethyldithiocarbamate as zinc source and sulfur source,ZnS/CFs composite materials were successfully prepared through subsequent calcination treatment.The systematic study of the impact of varied metal contents on the morphology and electrochemical characteristics of materials.When subjected to 240 cycles,the improved ZnS/CFs composite maintains a capacity of 768.1 m Ah g^-1at a current density of 200 m A g^-1.However,when subjected to a current density of 1 A g^-1,the lithium storage capacity of the material declines rapidly.The specific capacity is only 268 m Ah g^-1after 1000cycles.To increase the stability of ZnS/carbon fiber composites during the rapid charge-discharge process,soft templating agent P123 was added to the spinning precursor,resulting in a higher specific surface area for the ZnS/porous carbon fiber composites.The composites maintain a capacity of 788.7 m Ah g^-1after 240 cycles at a current density of 200 m A g^-1.In addition,the durability of composites during fast charge-discharge has been significantly enhanced,it can now retain a stable capacity of 592.2 m Ah g^-1after 1000 cycles at 1 A g^-1current density.For the purpose of further improving the specific capacity of the material,ZnS/Fe S/PCFs composites were successfully prepared by adding ferrous sulfide（Fe S）to ZnS/PCFs.The synergistic effect of ZnS and Fe S is used to optimize lithium storage performance.The results show outstanding performance.When the material circulates 150 cycles at a current density of 200 m A g^-1,its capacity remains at 1208.9m Ah g^-1;under the current density of 1 A g^-1,the specific capacity can be maintained at 702.2 m Ah g^-1after 1000 cycles and exhibited excellent rate performance.