电工电能新技术

作者：TIAN Xue?qin1, FENG Cai?mei2, JIANG Han3, MA Shi?yi1, CHEN Yong?chong2, LIU Dan?dan2, ZHAO Teng3

单位：1. State Grid Economic and Technological Research Institute Co., Ltd., Beijing 102209, China；
\r\n2. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China；
\r\n3. Global Energy Interconnection Group Co., Ltd., Beijing 100031, China

关键词：lithium slurry battery, current collector, surface modification, interface, electrochemical performance

Lithium slurry battery (LSB) is a new energy storage technology suitable for the application in low?speed electric vehicles, base stations, household cases and power grid. Contact resistance between the current collector and the electrode slurry is critical for the electrochemical performance of this technique. In the present work, Al matrixes were decorated with different ratios of carbon black (CB) and polyvinylidene fluoride (PVDF) to investigate the influence of current collector surface treatment on LiFePO4 half slurry cells. Results showed that the ratio of CB and PVDF affected the homogeneity, the microcrack formation, the surface area, the porosity and the adhesion of the coating layer, leading to different electronic and ionic resistances. When the content of CB is too high, the insufficient adhesion agent was not able to accommodate the high surface tension of the CB nanoparticles during drying process, forming cracks and increasing contact resistance. The specific surface area and pore volume of the coating layer was found to first increase and then decrease as the ratio of CB∶PVDF increased from 1∶1 to 5∶1, with a maximum around 3∶1. This phenomenon was consistent with the measured ohmic resistance and charge/discharge profiles. Larger porosity and surface area of the coating layer were beneficial for the transfer of lithium ions in the electrolyte and the electrochemical reactions. Finally, a specific capacity of 149?2(mA·h)/g at 0?2mA/cm2 was obtained for LiFePO4 half slurry cell using the optimized Al mesh current collector with a coating ratio of 3∶1 (CB∶PVDF).

来源：2019年第9期

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