基于弱配位环境的晶态锌离子固态电解质  

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

作　　者：许超锋 韩晓蕾 王进芝 王晓君 刘治明 赵井文[2,3,4] XU Chaofeng;HAN Xiaolei;WANG Jinzhi;WANG Xiaojun;LIU Zhiming;ZHAO Jingwen(College of Electromechanical Engineering,Qingdao University of Science&Technology,Qingdao 266061,Shandong,China;Qingdao Institute of Bioenergy and Bioprocess Technology,Chinese Academy of Sciences;Shandong Energy Institute;Qingdao New Energy Shandong Laboratory,Qingdao 266101,Shandong,China)

机构地区：[1]青岛科技大学机电工程学院,山东青岛266061 [2]中国科学院青岛生物能源与过程研究所 [3]山东能源研究院 [4]青岛新能源山东省实验室,山东青岛266101

出　　处：《储能科学与技术》2024年第8期2519-2528,共10页Energy Storage Science and Technology

基　　金：泰山学者工程资助(tsqn202211277);山东省自然科学基金(ZR2023YQ010);青海盐湖工业股份有限公司科技计划项目(1000000-23-ZC0609-0002)。

摘　　要：二次锌电池是一类低成本、环保和高安全的规模储能技术,但是一直以来锌金属负极与传统水系电解液兼容性不足以及严重的枝晶生长问题限制了电池能量密度和寿命。发展固态二次锌电池是根本解决上述瓶颈问题的有效路线之一,但是,二价锌离子电荷密度高,其在无机陶瓷电解质和聚合物电解质中的室温固相传导极为困难。本工作以具有层状晶体结构的三氟甲基磺酸锌[Zn(TFO)_(2)]作为离子盐主体骨架,通过引入“软碱”的双齿弱配位配体——丁二腈(SN)重塑锌离子的固相配位环境,发展了一类晶态配位化合物的锌离子固态电解质[Zn(TFO)_(2)(SN)_(n)]。得益于氰基官能团(—CN)与三氟甲基磺酸阴离子(TFO^(-))的共配位结构,阴离子骨架对锌离子的静电束缚得到了显著降低,锌离子室温固态离子电导率实现了3个数量级的提升[由Zn(TFO)_(2)的1.1×10^(-9)S/cm提升至1.8×10^(-6)S/cm]。基于该类固态电解质,Zn||Zn对称电池可实现低极化电压(0.08 V,0.05 mA/cm^(2))的长周期锌沉积/溶解循环,并且实现了全固态锌空气电池在室温下的可逆充放电。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/cm^(2))and the reversible charging and discharging of a solid zinc-air battery at room temperature.

关 键 词：晶态配位化合物 弱配位作用 锌离子固态电解质 锌离子固相传导 二次锌电池 

分 类 号：TM911[电气工程—电力电子与电力传动]