| With the advancement of science and technology,human beings are facing severe energy crisis and environmental pollution challenges.The field of energy storage has received extensive attention.Lithium-ion batteries(LIBs),as the most widely used commercial batteries,are currently one of the most commonly used energy storage devices,but they also have some limitations:short life,high cost and issues such as low energy density.Therefore,there is an urgent need to develop more efficient,cost-effective,and environmentally friendly anode materials and new batteries.At the same time,Aluminum ion battery(AIBs)is expected to become a new generation of energy storage system due to its abundant aluminum,easy mining and high energy density of three free electrons,efficient and durable,charging very fast.However,Al3+ is easy to form complex ion groups with large radius(AlxCly-)with Cl-,and the strong electrostatic interaction with positive electrode materials increases the energy barrier of ion group deintercalation.Therefore,the performance and cost of positive electrode materials restrict its further development.Among them,chalcopper CuFeS2(CFS)and CuFeO2(CFO)are expected to be developed into lithium/aluminum battery electrode materials due to their abundant reserves,diverse chemical reactions and high theoretical capacity.This paper takes CuFeS2 and CuFeO2 as the theme,and applies them to lithium/aluminum storage research.The specific research content is as follows:(1)CuFeS2 was prepared by solvothermal method and microwave solvothermal method,and CuFeS2@NC composite nitrogen carbon was prepared by chemical vapor deposition.The carbon layer on the surface of CuFeS2 can greatly improve its cycle performance and rate performance in lithium/aluminum batteries.This carbon composite structure can reduce the dissolution of polysulfides in the electrolyte,ease the volume expansion during charge and discharge and increasing the conductivity.After 300 cycles of CFS@10%C at a current density of 0.5 C in a lithium-ion battery,the specific discharge capacity remained at 878.6 mAh·g-1,which was 93.4%of the initial capacity,and the Coulombic efficiency remained above 98%.The capacity of CFS@30%C was maintained at 18.0 mAh·g-1 after 2000 cycles at a current density of 1 C in Al-ion batteries,and the Coulombic efficiency was increased to more than 90%.This study provides a feasible route to design highly conductive CuFeS2-based anode materials for Li-ion batteries and novel Al-ion cathode materials.(2)CuFeO2 was prepared by alkaline hydrothermal method,and its electrochemical performance in different lithium ion electrolytes was tested.The phase transition reaction of CuFeO2 in the process of charging and discharging was tested by in situ XRD.It was found that the characteristic peak shift was very small,and gradually became wider and disappeared with the embedding of lithium ions,and no new characteristic peak was generated during the charging process.Since no new characteristic peak is produced,it is speculated that the reaction mechanism may be a monophasic reaction,and CuFeO2 is transformed from crystalline to amorphous.With the intercalation of lithium ions,the crystallinity of CuFeO2 decreases,so the characteristic peak of CuFeO2 does not appear in the subsequent charging process.CuFeO2 was cycled at 0.2 C current density for 100 cycles in an Al ion cell to maintain a capacity of 12.9 mAh·g-1.This study speculated the reaction mechanism of CuFeO2 in lithium ion batteries and attempted to apply it to aluminum ion batteries,which promoted the research of CuFeO2 in lithium/aluminum storage performance. |
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