原位氮掺杂碳包覆CoxP复合物的制备及其锂电性能

以类沸石咪唑酯骨架化合物ZIF-67为钴源、碳源和氮源前驱体,红磷作为磷源,在800 ℃煅烧直接制备氮掺杂碳包覆的Co₂P@N-C和CoP@N-C复合物,并研究其作为锂离子电池负极材料的电化学性能。 结果表明,所得复合物的组分可以通过调控ZIF-67和红磷的比例而改变。 所得复合物的结构为正十二面体,尺寸约250~400 nm,具有良好的导电性。 用作锂离子电池电极材料时,在电流密度为0.05 A/g下,Co₂P@N-C和CoP@N-C复合物首次放电容量分别达到942和1170.6 mA·h/g。 在1 A/g的电流密度下,经过500次循环容量依然可以保持在306.6和180.3 mA·h/g。 论文提供了一种绿色环保制备锂电池用磷化钴/碳复合物的简易方法。

In Situ Synthesis of Nitrogen-Doped Carbon Coated CoxP Composites and Their Lithium Properties

Nitrogen-doped carbon coated Co₂P@N-C and CoP@N-C composites were in situ synthesized at 800 ℃ using zeolitic imidazolate framework-67 (ZIF-67) as cobalt/nitrogen/carbon precursor and red phosphorus as phosphorus source, and their electrochemical properties were studied as anode materials of lithium ion batteries. It is found that the resulted products can be tailored by the ratio of ZIF-67 to red phosphorus. The obtained Co₂P@N-C and CoP@N-C composites show regular dodecahedron and the size of about 250 to 400 nm and exhibit good conductivity. When they are used as anode materials, the first discharge capacity of the Co₂P@N-C and CoP@N-C composites are 942 and 1170.6 mA·h/g at the current density of 0.05 A/g, respectively. Even at the current density of 1 A/g, their capacities are maintained at 306.6 and 180.3 mA·h/g after 500 cycles, respectively. We have provided a green and easy method for the synthesis of Co_xP@C composites for lithium ion battery.