Chen Hangda, Huang Juanjuan, Tian Shuhao, Liu Li, Qin Tianfeng, Song Lei, Liu Yanpeng, Zhang Yanan, Wu Xiaogang, Lei Shulai, Peng Shanglong
National & Local Joint Engineering Laboratory for Optical Conversion Materials and Technology, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, P.R. China.
Department of Applied Physics, Eindhoven University of Technology, Eindhoven, 5600 MB, the Netherlands.
Adv Sci (Weinh). 2021 Jul;8(14):e2004924. doi: 10.1002/advs.202004924. Epub 2021 May 24.
The interlayer modification and the intercalation pseudocapacitance have been combined in vanadium oxide electrode for aqueous zinc-ion batteries. Intercalation pseudocapacitive hydrated vanadium oxide Mn V O ·12H O with defective crystal structure, interlayer water, and large interlayer distance has been prepared by a spontaneous chemical synthesis method. The inserted Mn forms coordination bonds with the oxygen of the host material and strengthens the interaction between the layers, preventing damage to the structure. Combined with the experimental data and DFT calculation, it is found that Mn refines the structure stability, adjusts the electronic structure, and improves the conductivity of hydrated vanadium oxide. Also, Mn changes the migration path of Zn , reduces the migration barrier, and improves the rate performance. Therefore, Mn -inserted hydrated vanadium oxide electrode delivers a high specific capacity of 456 mAh g at 0.2 A g , 173 mAh g at 40 A g , and a capacity retention of 80% over 5000 cycles at 10 A g . Furthermore, based on the calculated zinc ion mobility coefficient and Zn(H O) diffusion energy barrier, the possible migration behavior of Zn(H O) in vanadium oxide electrode has also been speculated, which will provide a new reference for understanding the migration behavior of hydrated zinc-ion.
层间修饰和嵌入赝电容已在水系锌离子电池的氧化钒电极中相结合。通过自发化学合成法制备了具有缺陷晶体结构、层间水和较大层间距的嵌入赝电容型水合氧化钒MnVO·12H₂O。插入的Mn与主体材料的氧形成配位键，增强了层间相互作用，防止结构受损。结合实验数据和密度泛函理论计算发现，Mn提高了水合氧化钒的结构稳定性，调整了电子结构，提高了其导电性。此外，Mn改变了Zn²⁺的迁移路径，降低了迁移势垒，提高了倍率性能。因此，插入Mn的水合氧化钒电极在0.2 A g⁻¹时具有456 mAh g⁻¹的高比容量，在40 A g⁻¹时为173 mAh g⁻¹，在10 A g⁻¹下5000次循环后的容量保持率为80%。此外，基于计算得到的锌离子迁移系数和Zn(H₂O)₄²⁺扩散能垒，还推测了Zn(H₂O)₄²⁺在氧化钒电极中的可能迁移行为，这将为理解水合锌离子的迁移行为提供新的参考。
