Cheng Yi, Sang Hongqian, Jiang Qike, Wang Haisong, Zhang Huamin, Li Xianfeng
School of Light Industry and Chemical Engineering , Dalian Polytechnic University , Dalian 116034 , China.
Institute for Interdisciplinary Research , Jianghan University , Wuhan 430056 , China.
ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28934-28942. doi: 10.1021/acsami.9b09335. Epub 2019 Aug 2.
Pomegranate-like LiV(PO)@C (LVP@C) cathode materials are fabricated through confined effect helped by the vacuum-assisted capillary action. The performance of LiV(PO) ( = 0-5) at an extended working voltage of 1.2-4.8 V has been studied by operando X-ray powder diffraction and hybrid functional density functional theory (DFT) calculation. The DFT calculation results suggest that LiV(PO) can be intercalated with another two Li with a stable crystalline structure, which improves the specific capacity of LVP significantly. The cathode exhibits a specific capacity of 320 mAh g with an energy density of 736 Wh kg, which is one of the best performances for intercalation cathode materials for Li-ion batteries to our knowledge. Besides, the cathode showed excellent rate capability. In the working potential of 3.0-4.8 V, it exhibits a high specific capacity of 195 mAh g at 0.2 C, and even at a high rate of 30 C, it still delivers the specific capacity of 145 mAh g with a power density of 15.93 kW kg. The good performance is mainly attributed to the unique pomegranate structure, which can provide continuous three-dimensional conductive networks for fast electron and Li-ion transfer. This paper provides a new strategy for synthesizing other cathode or anode materials with high energy and power density.
通过真空辅助毛细作用产生的限域效应制备了石榴石状的LiV(PO)@C（LVP@C）正极材料。通过原位X射线粉末衍射和杂化泛函密度泛函理论（DFT）计算研究了LiV(PO)（=0 - 5）在1.2 - 4.8 V扩展工作电压下的性能。DFT计算结果表明，LiV(PO)可以再嵌入另外两个Li并具有稳定的晶体结构，这显著提高了LVP的比容量。该正极表现出320 mAh g的比容量和736 Wh kg的能量密度，据我们所知，这是锂离子电池嵌入型正极材料的最佳性能之一。此外，该正极还表现出优异的倍率性能。在3.0 - 4.8 V的工作电位下，它在0.2 C时表现出195 mAh g的高比容量，甚至在30 C的高倍率下，仍能提供145 mAh g的比容量和15.93 kW kg的功率密度。良好的性能主要归因于独特的石榴石结构，它可以为快速的电子和锂离子传输提供连续的三维导电网络。本文为合成其他具有高能量和功率密度的正极或负极材料提供了一种新策略。
