Aqueous Zn-MnO2 battery: Approaching the energy storage limit with deep Zn2+ pre-intercalation and revealing the ions insertion/extraction mechanisms

作者：Yaxiong Zhang, Xiaosha Cui, Yupeng Liu, Situo Cheng, Peng Cui, Yin Wu, Zhenheng Sun, Zhipeng Shao, Jiecai Fu, Erqing Xie · 发表于：Journal of Energy Chemistry · 年份：2021 · DOI：10.1016/j.jechem.2021.09.038 · 被引用次数：75 · 研究领域：Advanced battery technologies research、Advanced Battery Materials and Technologies、Supercapacitor Materials and Fabrication

Rechargeable aqueous zinc ion batteries (AZIBs) were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness. As AZIBs cathode material, MnO 2 possesses great merits but was greatly hindered due to the sluggish diffusion kinetic of Zn 2+ during electrochemical operations. Herein, deep Zn 2+ ions intercalated δ-MnO 2 (Zn-MnO 2 ) was achieved by the in situ electrochemical deposition route, which significantly enhanced the diffusion ability of Zn 2+ due to the synergistic effects of Zn 2+ pillars and structural H 2 O. The resultant Zn-MnO 2 based AZIBs delivers a record capacity of 696 mAh/g (0.5 mAh/cm 2 ) based on the initial mass loading, which is approaching the theoretical capacity of MnO 2 with a two-electrons reaction. In-situ Raman studies reveal highly reversible Zn 2+ ions insertion/extraction behaviors and here the Zn-MnO 2 plays the role of a container during the charge–discharge process. Further charge storage mechanism investigations point out the insertion/extraction of Zn 2+ and H + coincides, and such process is significantly facilitated results from superior interlayered configurations of Zn-MnO 2. The excellent electrochemical performance of Zn-MnO 2 achieved in this work suggests the deep ions pre-intercalation strategy may aid in the future development of advanced cathodes for AZIBs.