碳热还原法制备lifepo,4及其性能研究-冶金物理化学专业论文.docx

中南大学硕士学位论文 ABSTRACTABSTRACTOlivine．type LiFeP04 has attracted particular attention due to the high safety,the inexpensive price and the relative lace of toxicity． However,the key barrier limiting its application is extremely low electronic conductivity and ionic conductivity．And its cycle ability at large charge／discharge current should be improved．Research must be carried out SO as to improve the conductivity and lithium diffusivity．This thesis focuses on olivine LiFeP04 synthesis by carbothermal reduction method and electrochemical performances．1)Study on the electrochemical performances of LiFeP04／C byusing carbon as reductantsThe effects of the amount of acetylene black，synthesis temperature and reaction time are discussed．砀e results show that纺e amount ofacetylene black,synthesis temperature and time influence the performances of the products．The products with 1 0．8％carbon content and sintered at 700C for 8h possessed excellent electrochemical performance．2)Study on the electrochemical performances of LiFePOdC by using glucose as reductantsThe effects of the amount of glucose，synthesis temperature andreaction time are discussed．The results show that the amount of glucose， synthesis temperature and time influence the performances of the products．ne products with 1 0．1％carbon content and sintered at 700℃ for 8h possessed excellent electrochemical performance．3)Comparison of electrochemical performances of LiFePo们bysolid state reaction using carbon and glucose as reductantsComparing electrochemical performances，crystalline structure， granularity and morphology of particles of LiFePOdC synthesized with different reductant sources，we conclude that LiFeP04／C prepared using glucose has better capacity and cycle performance．The specific dischargecapacities of LiFePO犯using glucose as reductants are 1 56．5，1 34．8 and 131．6mAh／g at O．1C，O．5C and 1C respectively，and after 30 cycles the specific discharge capacities are 1 5 1．3，1 28．6 and 1 22．7mAh／g．II中南大学硕士学位论文ABSTRACT4)S