Zhou Weijun, Chen Jizhang, Chen Minfeng, Xu Xinwu, Tian Qinghua, Xu Junling, Wong Ching-Ping
College of Materials Science and Engineering, Nanjing Forestry University Nanjing 210037 China
Department of Chemistry, School of Sciences, Zhejiang Sci-Tech University Hangzhou 310018 China.
RSC Adv. 2019 Sep 26;9(52):30556-30564. doi: 10.1039/c9ra06143f. eCollection 2019 Sep 23.
Aqueous zinc-ion batteries offer a low-cost and high-safety alternative for next-generation electrochemical energy storage, whereas suitable cathode materials remain to be explored. Herein, rod-like anhydrous VO derived from a vanadium-based metal-organic framework is investigated. Interestingly, this material is assembled by tiny nanosheets with a large surface area of 218 m g and high pore volume of 0.96 cm g. Benefiting from morphological and structural merits, this material exhibits excellent performances, such as high reversible capacity (449.8 mA h g at 0.1 A g), good rate capability (314.3 mA h g at 2 A g), and great long-term cyclability (86.8% capacity retention after 2000 cycles at 2 A g), which are significantly superior to the control sample. Such great performances are found to derive from high Zn ion diffusion coefficient, large contribution of intercalation pseudocapacitance, and fast electrochemical kinetics. The measurements unveil that the intercalation of Zn ion is accompanied by the reversible V reduction and HO incorporation. This work discloses a direction for designing and fabricating high-performance cathode materials for zinc-ion batteries and other advanced energy storage systems.
水系锌离子电池为下一代电化学储能提供了一种低成本、高安全性的替代方案，然而合适的阴极材料仍有待探索。在此，对源自钒基金属有机框架的棒状无水VO进行了研究。有趣的是，这种材料由微小的纳米片组装而成，具有218 m²/g的大表面积和0.96 cm³/g的高孔容。受益于形态和结构优点，这种材料表现出优异的性能，如高可逆容量（在0.1 A/g时为449.8 mA h/g）、良好的倍率性能（在2 A/g时为314.3 mA h/g）以及出色的长期循环稳定性（在2 A/g下2000次循环后容量保持率为86.8%），这些均显著优于对照样品。发现如此优异的性能源自高的锌离子扩散系数、嵌入赝电容的大贡献以及快速的电化学动力学。测量结果揭示，锌离子的嵌入伴随着可逆的V还原和H₂O掺入。这项工作为设计和制造用于锌离子电池及其他先进储能系统的高性能阴极材料指明了方向。
