Dai Yuhang, Liao Xiaobin, Yu Ruohan, Li Jinghao, Li Jiantao, Tan Shuangshuang, He Pan, An Qinyou, Wei Qiulong, Chen Lineng, Hong Xufeng, Zhao Kangning, Ren Yang, Wu Jinsong, Zhao Yan, Mai Liqiang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China.
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, China.
Adv Mater. 2021 Jul;33(26):e2100359. doi: 10.1002/adma.202100359. Epub 2021 May 17.
Aqueous zinc-ion batteries are highly desirable for large-scale energy storage because of their low cost and high-level safety. However, achieving high energy and high power densities simultaneously is challenging. Herein, a VO sub-nanometer cluster/reduced graphene oxide (rGO) cathode material composed of interfacial VOC bonds is artificially constructed. Therein, a new mechanism is revealed, where Zn ions are predominantly stored at the interface between VO and rGO, which causes anomalous valence changes compared to conventional mechanisms and exploits the storage ability of non-energy-storing active yet highly conductive rGO. Further, this interface-dominated storage triggers decoupled transport of electrons/Zn ions, and the reversible destruction/reconstruction allows the interface to store more ions than the bulk. Finally, an ultrahigh rate capability (174.4 mAh g at 100 A g , i.e., capacity retention of 39.4% for a 1000-fold increase in current density) and a high capacity (443 mAh g at 100 mA g , exceeding the theoretical capacities of each interfacial component) are achieved. Such interface-dominated storage is an exciting way to build high-energy- and high-power-density devices.
水系锌离子电池因其低成本和高安全性而非常适合大规模储能。然而，同时实现高能量密度和高功率密度具有挑战性。在此，人工构建了一种由界面VOC键组成的VO亚纳米团簇/还原氧化石墨烯（rGO）阴极材料。其中，揭示了一种新机制，即锌离子主要存储在VO和rGO之间的界面处，这与传统机制相比会导致异常的价态变化，并利用了非储能活性但高导电性的rGO的存储能力。此外，这种界面主导的存储引发了电子/锌离子的解耦传输，并且可逆的破坏/重建使界面能够比本体存储更多的离子。最后，实现了超高倍率性能（在100 A g下为174.4 mAh g，即电流密度增加1000倍时容量保持率为39.4%）和高容量（在100 mA g下为443 mAh g，超过每个界面组分的理论容量）。这种界面主导的存储是构建高能量密度和高功率密度器件的一种令人兴奋的方式。
