碳包覆磷酸铁锂二次介孔微球的制备及其电化学性能

Preparation and Electrochemical Performance of a Secondary Mesoporous LiFePO_4/C Microsphere

为提高磷酸铁锂的比容量和振实密度,采用简单易控制的水热法,以廉价的三价铁盐为铁源,制备具有碳包覆的二次介孔磷酸铁锂微球材料。应用X射线衍射和扫描电镜研究了二次介孔微球的微观结构和形貌。这种独特的等级结构微球能够紧密堆积,具有较高的振实密度,同时介孔有助于电解液进入微米球内部,利于电解液与活性物质的充分接触,从而使得材料表现出较好的电化学性能,在1C、5C、10C和20C时的比容量分别是137mAh.g-1、118mAh.g-1、109mAh.g-1和102mAh.g-1。

To enhance the specific capacity and tap densit LiFeP04/C microsphere was synthesized by a simple and controllable y of LiFePO4, a secondary mesoporous hydrothermal method using low-cost Fe3＋ salt as the raw material. Microstructural and morphological charaterization of the secondary mesoporous microsphere was studied using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Benefiting from this unique hierarchical architecture, these microspheres could be densely packed together, giving a relatively high tap density. Simultaneously, the mesoporous structure could provide a huge electrochemically available surface for the active materials and electrolyte, and LiFePO4/C microsphere exhibited the improved electrochemical performance. It delivers capacities of 137mAh.g 1, 118mAh·g^-1, 109 mAh·g^-1 and 102mAho g-lat 1C, 5C, 10C and 20C, respectively.