Announcement for Downloading full text filePlease respect the Copyright Act.
All digital full text dissertation and theses from this website are authorized the copyright owners. These copyrighted full-text dissertation and theses can be only used for academic, research and non-commercial purposes. Users of this website can search, read, and print for personal usage. In respect of the Copyright Act of the Republic of China, please do not reproduce, distribute, change, or edit the content of these dissertations and theses without any permission. Please do not create any work based upon a pre-existing work by reproduction, Adaptation, Distribution or other means.
URN etd-0818108-165537 Statistics This thesis had been viewed 4088 times. Download 1356 times. Author Mao-Sung Chen Author's Email Address email@example.com Department Materials Engineering Year 2007 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 73 Title Effects of Al3+ ion substitution of LiFe1-xAlxPO4/ MCMB on the cycle properties and capacity fading mechanism Keyword capacity fading olivine structure cathode materials cathode materials olivine structure capacity fading Abstract A solution method was used to synthesize LiFePO4 and Al3+-doped LiFe1-xAlxPO4 (0 £ x £ 0.1) powders. After heat-treatment at 700oC for 8 hours under N2 flowing atmosphere, the crystalline structure, compositions, and morphology of the prepared powders were investigated with the XRD patterns performed with 01C beamline of NSRRC of Taiwan, ICP-OES, and SEM. The powder with composition of LiFe0.95Al0.05PO4 shows the best cycling performance at room temperature among the prepared samples. The effects of Al3+-doping on the cycling performance of the LiFePO4/ Li coin-type cells and LiFePO4/ MCMB were investigated. From the cycling results of LiFePO4/ Li cells and the results of GSAS refinement, it was found the reversible capacity of LiFePO4 was increased by Al3+-substitution due to the enlargements of lattice parameter. From the results of capacity retention study for the LiFe1-xAlxPO4/ MCMB stacked cells, the high resolution X-ray image observation, and soaking study, it was revealed that the cycling performance of improvement in LiFe1-xAlxPO4/ MCMB cells by Al3+-substitution was attributed to the suppression of Fe2+-dissolution into LiPF6 electrolyte. Advisor Committee Hong-Ming Lin - advisor
She-Huang Wu - advisor
Ru-Shi Liu - co-chair
Wen-Chang Chen - co-chair
Files Date of Defense 2008-07-15 Date of Submission 2008-08-21