Improving lithium-ion transport in electrodes by controlling electrode microstructure is a promising option for enhancing the fast-charging capability of graphite anodes in lithium-ion batteries. Dry processing of electrodes based on a polytetrafluoroethylene binder has attracted considerable attention as an alternative to solvent-based wet processing. The morphology of graphite particles has a significant impact on electrode microstructure, but few reports have been published on dry-processed graphite anodes. In this work, we found that the morphology of graphite particles is a key factor to determine the fast-charging capability of the dry-processed graphite electrode as well as the microstructure of the dry-processed graphite electrode. X-ray microscopy combined with mercury porosimetry and symmetrical cell electrochemical impedance spectroscopy reveal that the difference in porosity between the top and bottom layers of a dry electrode with spherical graphite particles is greater than that of flake-shaped graphite particles, resulting in enhanced lithium-ion transport in the electrode and improved fast-charging capability at a high charging rate of 5C (17.5 mA cm). These findings supply insights into the effective design of dry-processed graphite anodes with an emphasis on fast-charging capability as well as the development of graphite anode materials for dry-processing based lithium-ion batteries.

中文翻译：

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锂离子电池干法石墨电极颗粒形状与快充能力的关系


通过控制电极微观结构来改善电极中的锂离子传输是增强锂离子电池石墨阳极快速充电能力的一个有前景的选择。作为溶剂型湿法加工的替代方案，基于聚四氟乙烯粘合剂的电极干法加工引起了相当大的关注。石墨颗粒的形貌对电极微观结构有显着影响，但有关干法石墨阳极的报道很少。在这项工作中，我们发现石墨颗粒的形貌是决定干法石墨电极快速充电能力以及干法石墨电极微观结构的关键因素。 X射线显微镜结合汞孔隙率测定法和对称电池电化学阻抗谱表明，具有球形石墨颗粒的干电极的顶层和底层之间的孔隙率差异大于片状石墨颗粒，从而增强了锂-电极中的离子传输以及在 5C (17.5 mA cm) 高充电速率下改进的快速充电能力。这些发现为干法石墨负极的有效设计提供了见解，重点是快速充电能力以及用于干法锂离子电池的石墨负极材料的开发。