State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Hubei, Wuhan, 430070, China.
School of Materials Science and Engineering, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Institute of New Energy Material Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), National Institute for Advanced Materials, Nankai University, Tianjin, 300071, China.
Adv Mater. 2018 Aug;30(32):e1801984. doi: 10.1002/adma.201801984. Epub 2018 Jun 25.
Owing to the low-cost, safety, dendrite-free formation, and two-electron redox properties of magnesium (Mg), rechargeable Mg batteries are considered as promising next-generation secondary batteries with high specific capacity and energy density. However, the clumsy Mg with high polarity inclines to sluggish Mg insertion/deinsertion, leading to inadequate reversible capacity and rate performance. Herein, 2D VOPO nanosheets with expanded interlayer spacing (1.42 nm) are prepared and applied in rechargeable magnesium batteries for the first time. The interlayer expansion provides enough diffusion space for fast kinetics of MgCl ion flux with low polarization. Benefiting from the structural configuration, the Mg battery exhibits a remarkable reversible capacity of 310 mAh g at 50 mA g , excellent rate capability, and good cycling stability (192 mAh g at 100 mA g even after 500 cycles). In addition, density functional theory (DFT) computations are conducted to understand the electrode behavior with decreased MgCl migration energy barrier compared with Mg . This approach, based on the regulation of interlayer distance to control cation insertion, represents a promising guideline for electrode material design on the development of advanced secondary multivalent-ion batteries.
由于镁 (Mg) 的低成本、安全性、无枝晶形成和两电子氧化还原特性，可充电 Mg 电池被认为是具有高比容量和能量密度的下一代二次电池。然而，极性较高的笨拙镁倾向于缓慢的 Mg 插入/脱插，导致可逆容量和倍率性能不足。在此，首次制备了具有扩展层间距（1.42nm）的二维 VOPO 纳米片，并将其应用于可充电镁电池。层间扩展为 MgCl 离子流的快速动力学提供了足够的扩散空间，极化较低。得益于这种结构配置，Mg 电池表现出显著的可逆容量，在 50mA g 的电流密度下为 310mAh g ，优异的倍率性能和良好的循环稳定性（在 100mA g 的电流密度下，甚至在 500 次循环后仍为 192mAh g ）。此外，进行了密度泛函理论（DFT）计算，以了解与 Mg 相比，MgCl 迁移能垒降低的电极行为。这种基于调节层间距来控制阳离子插入的方法，为先进的二次多价离子电池的电极材料设计提供了有前途的指导。
