Chilufya Langson, Sertbaş Vahide, Aytekin Ahmet, Karabudak Engin, Emirdag-Eanes Mehtap
Department of Chemistry, Faculty of Science, Izmir Institute of Technology, Gülbahçe Campus 35430 Urla, İzmir 35050, Turkey.
ACS Omega. 2025 Aug 5;10(32):36536-36549. doi: 10.1021/acsomega.5c05213. eCollection 2025 Aug 19.
Rechargeable aqueous zinc-ion batteries (AZIBs) have become a viable option in electrochemical energy storage systems (EESS) owing to their inherent safety features and economic friendliness. Nonetheless, creating suitable cathode materials for AZIBs with high structural stability, good rate performance, and great capacity remains a significant challenge. Polyoxometalate (POM)-based nanohybrid materials have shown promising results in high cycling stability and great specific capacity. However, POMs susceptible to electrolyte dissolution and the sluggish Zn-ion (Zn) kinetics have significantly hampered their electrochemical performance as cathodes for AZIBs. Herein, we present a Keggin POM, K[PWO]·HO (KPW), anchored on hydroxyl (OH)-functionalized single-walled carbon nanotubes (SWOH) that were fabricated via a facile ultrasonication procedure. Employed as cathodes for AZIBs, the optimal KPW/SWOH feature exhibited remarkable electrochemical performance. The system satisfied the Zn storage, achieving a reversible discharge capacity of 183 mAh g at a high current density of 5C with a flat and long discharge plateau after 160 cycles. The perfect synergistic contribution of the pseudocapacitive nature of the super-reduced state of KPW and the electron-conductive network of SWOH was attributed to this exceptional electrochemical performance. Furthermore, the presence of oxygen in SWOH enhanced the transfer kinetics of electrons and smooth Zn diffusion while lowering the Zn migration energy barrier by providing more accessible active sites. This demonstrates remarkable promise in fabricating robust electrode materials optimized for integration within aqueous battery systems that pave the way for further research into POM-based materials for EESS.
可充电水系锌离子电池（AZIBs）因其固有的安全特性和经济友好性，已成为电化学储能系统（EESS）中一个可行的选择。尽管如此，为AZIBs制备具有高结构稳定性、良好倍率性能和高容量的合适正极材料仍然是一项重大挑战。基于多金属氧酸盐（POM）的纳米杂化材料在高循环稳定性和高比容量方面已显示出有前景的结果。然而，易受电解质溶解影响的POMs以及缓慢的锌离子（Zn）动力学严重阻碍了它们作为AZIBs正极的电化学性能。在此，我们展示了一种锚定在通过简便超声处理制备的羟基（OH）功能化单壁碳纳米管（SWOH）上的Keggin型POM，K[PWO]·HO（KPW）。用作AZIBs的正极时，最佳的KPW/SWOH表现出卓越的电化学性能。该体系实现了锌存储，在5C的高电流密度下具有183 mAh g的可逆放电容量，经过160次循环后具有平坦且长的放电平台。KPW的超还原态的赝电容性质与SWOH的电子导电网络的完美协同作用归因于这种优异的电化学性能。此外，SWOH中氧的存在增强了电子转移动力学并使锌扩散顺畅，同时通过提供更多可及的活性位点降低了锌迁移能垒。这在制备为集成到水系电池系统而优化的坚固电极材料方面显示出显著的前景，为进一步研究用于EESS的基于POM的材料铺平了道路。
