Paik Sanga, Choi Inyoung, Lee Siyeon, Nam Kwan Woo
Department of Chemical Engineering and Materials Science, and Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
ACS Appl Mater Interfaces. 2024 Sep 25;16(38):50775-50784. doi: 10.1021/acsami.4c10537. Epub 2024 Sep 13.
Aqueous rechargeable zinc-ion batteries (ARZBs) are promising energy storage systems (ESSs) due to lots of advantages, such as high safety, high capacity, abundant resources, and low cost. However, the tunnel-structured Mn-based cathode materials such as α, β, and γ-MnO, which is widely used as the cathode of ARZBs, contain a phase transition in which Mn ions are eluted during the discharge reaction of Zn insertion, resulting in decreasing cycle life and rate capability of the ARZBs. Here, in order to enhance the cycle life and rate capability of ARZBs by retaining eluted Mn ions around the β-MnO cathode during the discharge process, tannic acid (TA), a type of polyphenolic biomolecule containing rich -OH groups, is introduced as a coating material. This provides a chelating effect with the eluted Mn ions and hydroxyl groups on the surface of the β-MnO cathode. This study clearly shows that the TA coating improves the performance of the cathode material by using a range of analytical methods. Owing to the chelating effects of TA, TA-coated β-MnO cathode shows a high discharge capacity of 268.2 mAh g at the current of 100 mA g and 86.8% of high capacity retention after 50 cycles. This study provides the coating agents with chelating effects to develop Zn//MnO battery chemistry and further improve large ESSs through high electrochemical performance.
水系可充电锌离子电池（ARZBs）因其具有高安全性、高容量、资源丰富和低成本等诸多优点，是很有前景的储能系统（ESSs）。然而，作为ARZBs阴极广泛使用的隧道结构锰基阴极材料，如α、β和γ-MnO，在锌嵌入的放电反应过程中存在一个相变，其中锰离子会被洗脱，导致ARZBs的循环寿命和倍率性能下降。在此，为了通过在放电过程中将洗脱的锰离子保留在β-MnO阴极周围来提高ARZBs的循环寿命和倍率性能，引入了单宁酸（TA），一种含有丰富-OH基团的多酚类生物分子作为涂层材料。这与洗脱的锰离子和β-MnO阴极表面的羟基产生螯合作用。本研究通过一系列分析方法清楚地表明，TA涂层提高了阴极材料的性能。由于TA的螯合作用，TA包覆的β-MnO阴极在100 mA g的电流下显示出268.2 mAh g的高放电容量，并且在50次循环后具有86.8%的高容量保持率。本研究为开发Zn//MnO电池化学并通过高电化学性能进一步改进大型ESSs提供了具有螯合作用的涂层剂。
