Abstract:

The development of low-cost, high-performance cathodes is one of the major research goals for next-generation rechargeable lithium and lithium-ion batteries. As a promising alternative to traditional intercalated electrode materials, metal fluorides offer much higher theoretical capacity and energy density than conventional cathodes. Herein, a self-assembled iron fluoride/carbon/porous graphene oxide (FeF₃/C/HRGO) cathode material covered by vertical porous carbon structure was designed and fabricated. This vertical porous carbon structure presents a double-layer carbon-clad frame with primary and secondary carbon-clad layers. Among them, the primary carbon shell generated by glucose wraps around FeF₃ nanoparticles which effectively inhibits the growth of particle volume during fluorination process. Meanwhile, the porous conductive network in the secondary carbon-clad layer significantly shortens the transport path of Li⁺ and increase the electronic conductivity. As a result, the FeF₃/C/HRGO electrode delivered an excellent reversible capacity of 406 mAh·g^-1 after 200 cycles at 0.1 A·g^-1.

Key words: FeF₃, porous graphene oxide, Li-ion battery, cathode, synthesis, electrochemistry, nanomaterials

摘要：

开发低成本、高性能的正极是下一代可充电锂电池和锂离子电池的主要研究目标之一。针对此，设计并制备了一种具有垂直多孔碳包覆结构的自组装氟化铁/碳/多孔还原氧化石墨烯（FeF₃/C/HRGO）正极材料。通过结合水热合成与静电自组装，该复合正极材料拥有包含初级、次级碳包覆层的双层碳包覆框架。其中球形结构的初级碳包覆层有效抑制了氟化过程中FeF₃的体积膨胀，而次级碳包覆层中的多孔导电网络，显著促进了电极内部的电子传输与离子迁移。在0.1 A·g^-1的电流密度下，所得FeF₃/C/HRGO复合正极经过200次充放电循环后，仍保持有406 mAh·g^-1的优异可逆容量。

关键词: 氟化铁, 多孔氧化石墨烯, 锂离子电池, 正极, 合成, 电化学, 纳米材料