Jin Xiaozhe, Tian Ruixue, Wu Aimin, Xiao Yadan, Dong Xufeng, Hu Fangyuan, Huang Hao
Key Laboratory of Energy Materials and Devices (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, Liaoning Province, China.
Dalton Trans. 2020 Feb 21;49(7):2225-2233. doi: 10.1039/c9dt04444b. Epub 2020 Jan 31.
Transition metal phosphides have been receiving a great deal of attention as anode materials for Li-ion batteries due to their novel properties of high theoretical capacity and relatively low polarization. MoP and MoP nanoparticles with different crystal structures are synthesized by phosphorization in different stoichiometric proportions, using Mo nanospheres as the precursor produced by the plasma evaporation method. When used as the anode material for Li-ion batteries, the MoP electrode delivers a stable capacity of 676.60 mA h g after 300 cycles at a current density of 0.1 A g with obvious discharge/charge plateaus; however, the capacity of the hexagonal MoP electrode is 312.38 mA h g. The first-principles calculations illustrate that the di-phosphorus bond of MoP is prone to break and the distal P atoms preferentially bind with Li atoms to form LiP during lithiation, but MoP prefers to form ternary LiMoP. The ex situ X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) of the MoP electrode after cycling confirm the conversion reaction for the electrochemical storage of Li-ions.
过渡金属磷化物因其具有高理论容量和相对低极化的新颖特性，作为锂离子电池的负极材料受到了广泛关注。以通过等离子体蒸发法制备的Mo纳米球为前驱体，采用不同化学计量比的磷化反应合成了具有不同晶体结构的MoP和MoP纳米颗粒。当用作锂离子电池的负极材料时，MoP电极在0.1 A g的电流密度下循环300次后，提供了676.60 mA h g的稳定容量，具有明显的充放电平台；然而，六方MoP电极的容量为312.38 mA h g。第一性原理计算表明，MoP的双磷键易于断裂，在锂化过程中，远端P原子优先与Li原子结合形成LiP，但MoP更倾向于形成三元LiMoP。循环后的MoP电极的非原位X射线衍射（XRD）和高分辨率透射电子显微镜（HRTEM）证实了锂离子电化学存储的转化反应。
