Energy Storage Science and Technology ›› 2024, Vol. 13 ›› Issue (8): 2519-2528.doi: 10.19799/j.cnki.2095-4239.2024.0236

• Energy Storage Materials and Devices • Previous Articles     Next Articles

Crystalline zinc-ion solid-state electrolytes based on weak coordination environments

Chaofeng XU1,2(), Xiaolei HAN1,2, Jinzhi WANG2,3,4, Xiaojun WANG1(), Zhiming LIU1(), Jingwen ZHAO2,3,4()   

  1. 1.College of Electromechanical Engineering, Qingdao University of Science&Technology, Qingdao 266061, Shandong, China
    2.Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
    3.Shandong Energy Institute
    4.Qingdao New Energy Shandong Laboratory, Qingdao 266101, Shandong, China
  • Received:2024-03-18 Revised:2024-04-16 Online:2024-08-28 Published:2024-08-15
  • Contact: Xiaojun WANG, Zhiming LIU, Jingwen ZHAO E-mail:xucf@qibebt.ac.cn;wangxiaojunchem@163.com;zmliu@qust.edu.cn;zhaojw@qibebt.ac.cn

Abstract:

Secondary zinc batteries represent a low-cost, environmentally friendly, and highly safe energy storage technology. However, the insufficient compatibility of zinc-metal anodes with traditional aqueous electrolytes and the growth of zinc dendrites have long posed challenges to their energy density and operational lifespan. Developing solid-state secondary zinc batteries presents a practical pathway to address this bottleneck. However, the high-charge density of divalent zinc ions renders solid-state zinc-ion conduction in conventional ceramic and polymer electrolytes at room temperature exceedingly challenging. In this study, we leveraged zinc trifluoromethyl sulfonate [Zn(TFO)2] with an intrinsic layered crystal structure as the primary ionic salt framework. We reshaped the coordination environment of zinc ions by incorporating succinonitrile (SN), a bidentate, weakly coordinating ligand recognized for its soft base properties. We designed a new class of crystalline coordination compounds for zinc-ion solid electrolytes [Zn(TFO)2(SN) n ]. The co-coordination structure of the cyano group (—CN) and the trifluoromethyl anion (TFO-) significantly reduce the electrostatic constraint of the anion framework to zinc ions, leading to three orders of magnitude improvement in the room-temperature ion conductivity (from 1.1 × 10-9 S/cm for Zn(TFO)2 to approximately 1.8 × 10-6 S/cm). This solid electrolyte can support long-term zinc-plating/stripping cycles with low polarization voltages (0.08 V, 0.05 mA/cm2) and the reversible charging and discharging of a solid zinc-air battery at room temperature.

Key words: crystalline coordination compounds, weak coordination, zinc-ion solid-state electrolytes, solid-state zinc-ion conduction, secondary zinc batteries

CLC Number: