Stable zinc anode solid electrolyte interphase via inner Helmholtz plane engineering
Jinrong Luo, Liang Xu, Yinan Yang, Song Huang, Yijing Zhou, Yanyan Shao, Tianheng Wang, Jiaming Tian, Shaohua Guo, Jianqing Zhao, Xiaoxu Zhao, Tao Cheng, Yuanlong Shao, Jin Zhang, Yuanlong Shao, Jin Zhang
Abstract
The inner Helmholtz plane and thus derived solid-electrolyte interphase (SEI) are crucial interfacial structure to determine the electrochemical stability of Zn-ion battery (ZIB). In this work, we demonstrate that introducing β-cyclodextrins (CD) as anion-receptors into Zn(OTf)2 aqueous electrolyte could significantly optimize the Zn anode SEI structure for achieving stable ZIB. Specifically, β-CD with macrocyclic structure holds appropriate cavity size and charge distribution to encase OTf- anions at the Zn metal surface to form β-CD@OTf- dominated inner Helmholtz structure. Meanwhile, the electrochemically triggered β-CD@OTf- decomposition could in situ convert to the organic-inorganic hybrid SEI (ZnF2/ZnCO3/ZnS‒(C-O-C/*CF/*CF3)), which could efficiently hinder the Zn dendrite growth with maintain the proper SEI mechanical strength stability to guarantee the long-term stability. The thus-derived Zn | |Zn pouch cell (21 cm2 size) with β-CD-containing electrolyte exhibits a cumulative capacity of 6450 mAh−2 cm−2 at conditions of 10 mAh cm−2 high areal capacity. This work gives insights for reaching stable ZIB via electrolyte additive triggered SEI structure regulation. Here, the authors report that introducing βcyclodextrins (CD) as anion-receptors into Zn(OTf)2 aqueous electrolyte could significantly optimize the Zn anode SEI structure for achieving stable ZIB.