用于锂离子高体积储存致密石墨颗粒的湿法制备

A wet granulation method to prepare graphite particles with a high tap density for high volumetric energy density lithium-ion storage

  • 摘要: 石墨是锂离子电池使用最广泛的负极材料,提高石墨的球形度和密度是提高其能量密度的重要方法。本文报道了通过高剪切湿法制粒技术制备具有高振实密度石墨颗粒的一种简单方法,将两种石墨材料致密化为两种石墨颗粒,即湿法制粒的洋葱状碳(WG-GOC)和湿法制粒的人造石墨(WG-AG)。结果发现,与制粒前的原始石墨相比,WG-GOC的振实密度提高了约34%,WG-AG的振实密度提高了约44%。当作为锂离子电池负极时,在电流密度为50 mA g−1时,WG-GOC和WG-AG的体积容量分别增加了约35%和55%。此外,WG-GOC的倍率性能也得到了明显改善。在电流密度为2000 mA g−1时,WG-GOC的体积比容量增加了169.1%。电化学性能的显著提升得益于所制石墨颗粒具有更高的振实密度。因此,利用湿法制粒法开发了一种制备高振实密度石墨负极的简易方法,这有利于高容量电极的发展。

     

    Abstract: Graphite is the most widely used anode material for lithium ion batteries (LIBs). Increasing the sphericity and tap density of the graphite particles is important for improving their volumetric energy density. We report a simple approach to prepare high tap-density graphite granules by high-shear wet granulation. Graphitic onion-like carbon (GOC) and artificial graphite (AG) were densified into granules by wet-granulation to obtain WG-GOC and WG-AG, respectively. Results indicate that, compared with the original graphite before granulation, the tap densities of WG-GOC and WG-AG increased by 34% and 44%, respectively. The respective volumetric energy densities of WG-GOC and WG-AG increased by 35% and 55% at a current density of 50 mA g−1. The rate performance of WG-GOC was also significantly improved. The volumetric capacity of WG-GOC at a current density of 2 000 mA g−1 was 169.1% of the original GOC. The significant improvement of electrochemical performance is ascribed to the increased tap density of the graphite granules.

     

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