Zhao Xun, Mao Lei, Cheng Qihui, Liao Fangfang, Yang Guiyuan, Chen Lingyun
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China.
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China; National-Municipal Joint Engineering Laboratory for Chemical Process Intensification and Reaction, Chongqing University, Chongqing 401331, China.
J Colloid Interface Sci. 2022 Dec;627:1021-1029. doi: 10.1016/j.jcis.2022.07.119. Epub 2022 Jul 22.
At present, layered vanadium-oxygen structures have attracted wide attention for multivalent metal ion storage, especially in aqueous zinc-ion batteries (AZIBs), due to the attractive layered structure and large specific capacity based on V/V double electron transfer. However, in addition to a large specific capacity, a high output voltage is necessary to achieve a high specific energy density. Vanadium oxide and vanadate usually feature low working voltages, serious structural degradation and limited practical. To alleviate these problems, some cathode modification strategies have been proposed that improve the operating voltage, structural stability and diffusion kinetics of multivalent metal ions. In this paper, vanadyl phosphate (Na(VO)(PO)) nanosheets preintercalated with sodium ions and modified with oxygen vacancies were prepared via a facile one-step liquid phase treatment. The Na(VO)(PO) nanosheet cathode for AZIBs delivered a high specific capacity of 75.3 mAh g at 0.1 A g and retained 27.5 mAh g after 4000 cycles at 2 A g. Subsequently, the as-prepared Na(VO)(PO) nanosheets were physically and electrochemically characterized, and a possible mechanism of Zn insertion/extraction and structural decomposition was proposed based on ex situ XRD and XPS characterizations. Our work provides a simple method for simultaneously introducing sodium ion preintercalation and oxygen vacancies into vanadyl phosphate structures, and provides some insights into the zinc storage mechanism.
目前，层状钒氧结构因其具有吸引人的层状结构以及基于V/V双电子转移的大比容量，在多价金属离子存储方面引起了广泛关注，尤其是在水系锌离子电池（AZIBs）中。然而，除了大比容量外，为了实现高比能量密度，高输出电压也是必要的。氧化钒和钒酸盐通常具有低工作电压、严重的结构降解且实用性有限。为了缓解这些问题，已经提出了一些阴极改性策略，以提高多价金属离子的工作电压、结构稳定性和扩散动力学。在本文中，通过简便的一步液相处理制备了预先插入钠离子并经氧空位修饰的磷酸氧钒（Na(VO)(PO)）纳米片。用于AZIBs的Na(VO)(PO)纳米片阴极在0.1 A g下具有75.3 mAh g的高比容量，在2 A g下循环4000次后仍保留27.5 mAh g。随后，对所制备的Na(VO)(PO)纳米片进行了物理和电化学表征，并基于非原位XRD和XPS表征提出了锌嵌入/脱出及结构分解的可能机制。我们的工作提供了一种将钠离子预嵌入和氧空位同时引入磷酸氧钒结构的简单方法，并为锌存储机制提供了一些见解。
