Zhou Zhiyong, Zhang Jun, Duan He, Chen Siyuan, Yao Heng, Zhao Yanming, Kuang Quan, Fan Qinghua, Dong Youzhong
School of Physics and Optoelectronics, South China University of Technology, Guangzhou, 510640, P. R. China.
Ruyuan Dongyangguang Magnetic Materials Co., Ltd, Shaoguan, 512700, P. R. China.
Dalton Trans. 2021 Jun 1;50(21):7293-7304. doi: 10.1039/d1dt00983d.
The single-phase binary nickel vanadate Ni2V2O7 was successfully synthesized by a simple solid-state method to explore novel anode materials for lithium-ion batteries. After an activation process, the Ni2V2O7 electrode exhibited excellent electrochemical performance with a stable, high specific capacity of about 960 mA h g-1 at a current density of 100 mA g-1, which is attributed to the multiple valence states and the synergistic effect of the transition elements V and Ni. Even at a high current density of 2000 mA g-1, a stable specific capacity of about 400 mA h g-1 was still obtained. Considering the influence of the activation process on the electrochemical performance of the Ni2V2O7 electrode, we studied the origin of the excellent electrochemical performance, where the improved lithium diffusion coefficient and increased pseudocapacitive contribution caused by the activation process led to a significant improvement in the electrochemical performance, including rate capacity and cycle stability. By combining in situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) methods, for the first time, we illustrate the detailed lithium storage mechanism of the Ni2V2O7 electrode during the lithium insertion/extraction process.
通过简单的固态方法成功合成了单相二元钒酸镍Ni2V2O7，以探索用于锂离子电池的新型负极材料。经过活化过程后，Ni2V2O7电极表现出优异的电化学性能，在100 mA g-1的电流密度下具有稳定的高比容量，约为960 mA h g-1，这归因于过渡元素V和Ni的多价态以及协同效应。即使在2000 mA g-1的高电流密度下，仍可获得约400 mA h g-1的稳定比容量。考虑到活化过程对Ni2V2O7电极电化学性能的影响，我们研究了其优异电化学性能的起源，其中活化过程导致的锂扩散系数提高和赝电容贡献增加，使得包括倍率性能和循环稳定性在内的电化学性能得到显著改善。通过结合原位X射线衍射（XRD）和非原位X射线光电子能谱（XPS）方法，我们首次阐明了Ni2V2O7电极在锂嵌入/脱出过程中的详细储锂机制。
