Investigation of conductive carbons and electrode density on fast charging properties for LiFePO4 positive electrodes

• Main Authors: LIN, XIN-DIAN, 林新典
• Other Authors: Chang, Chia-Chin
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/27t42t

碩士 === 國立臺南大學 === 綠色能源科技學系碩士班 === 107 === Due to the unstable power generation of renewable energy and the shortage of oil, the demand for energy storage equipment has increased. Lithium-ion batteries (LIB) are considered to be promising energy storage devices in power grids, portable devices, and vehicles. Recently, in order to improve performance, LIB has made a lot of efforts. One of them is the fast charging capability, especially for electric vehicles. Considering the high safety requirement of electric vehicles, lithium iron phosphate (LiFePO4, LFP) is used as active materials for the positive electrode in LIBs. In this work, positive electrodes of addition of varied types of conductive carbon (Super P, KS-6, VGCF and Li-400), formulation ratio of materials for the positive electrode and conductive carbon (89.1%：6.9% and 90.2%：5.8%) and varied electrodes density (1.7~1.9, 1.9~2.1 and 2.1~2.3 g cm-3) are investigated to optimize the fast charging capability. Different rate charging, analysis of electrode surface morphology and porosimetry of different density are used to improve the verification of the positive electron conduction capability to achieve our high-rate charging. To our best practice, the electrode recipe performs good capacitance (128.7 mAh g-1) and capacity retention (77.77%) with electrode density 1.7~1.9 g cm-3 at 20 C charging rate.