1,3-Dimethyl-2-imidazolidinone: an ideal electrolyte solvent for high-performance Li–O;battery with pretreated Li anode  

1,3-二甲基咪唑啉酮:一种理想的溶剂用于含预处理负极的高性能锂氧气电池

作　　者：Zhimei Huang Jintao Meng Wang Zhang Yue Shen Yunhui Huang Zhimei Huang;Jintao Meng;Wang Zhang;Yue Shen;Yunhui Huang(State Key Laboratory of Material Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;College of Materials Science and Engineering,Shenzhen University,Shenzhen 518055,China)

机构地区：[1]State Key Laboratory of Material Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China [2]College of Materials Science and Engineering,Shenzhen University,Shenzhen 518055,China

出　　处：《Science Bulletin》2022年第2期141-150,M0003,共11页科学通报（英文版）

摘　　要：Electrolytes are widely considered as a key component in Li–O;batteries (LOBs) because they greatly affect the discharge-charge reaction kinetics and reversibility.Herein,we report that 1,3-dimethyl-2-imidazolidinone (DMI) is an excellent electrolyte solvent for LOBs.Comparing with conventional ether and sulfone based electrolytes,it has higher Li_(2)O_(2)and Li_(2)CO_(3)solubility,which on the one hand depresses cathode passivation during discharge,and on the other hand promotes the liquid-phase redox shuttling during charge,and consequently lowers the overpotential and improves the cyclability of the battery.However,despite the many advantages at the cathode side,DMI is not stable with bare Li anode.Thus,we have developed a pretreatment method to grow a protective artificial solid-state electrolyte interface(SEI) to prevent the unfavorable side-reactions on Li.The SEI film was formed via the reaction between fluorine-rich organic reagents and Li metal.It is composed of highly Li^(+)-conducting Li_(x)BO_(y),LiF,Li_(x)NO_(y),Li_(3)N particles and some organic compounds,in which Li_(x)BO_(y)serves as a binder to enhance its mechanical strength.With the protective SEI,the coulombic efficiency of Li plating/stripping in DMI electrolyte increased from 20%to 98.5%and the fixed capacity cycle life of the assembled LOB was elongated to205 rounds,which was almost fivefold of the cycle life in dimethyl sulfoxide (DMSO) or tetraglyme(TEGDME) based electrolytes.Our work demonstrates that molecular polarity and ionic solvation structure are the primary issues to be considered when designing high performance Li–O;battery electrolytes,and cross-linked artificial SEI is effective in improving the anodic stability.电解质被广泛认为是锂氧气电池中的关键成分,因为它极大地影响电池的充放电反应动力学和可逆性.本文提出了1,3-二甲基咪唑啉酮(DMI)作为一种极好的电解液溶剂用于锂氧气电池中,该溶剂与传统的醚类和砜类溶剂相比,对过氧化锂(Li_(2)O_(2))和碳酸锂(Li_(2)CO_(3))具有较高的溶解度,该性质不仅可抑制电池在放电时的正极钝化,同时可促进充电过程中的液相氧化还原反应,降低电池的过电位以及提高电池的循环性能.尽管DMI溶剂在正极方面具有多种优势,但DMI对金属锂负极不稳定.为此,本文开发了一种在金属锂表面构筑人工固态电解质膜(SEI)作为保护膜阻止锂表面副反应的方法.通过有机氟化试剂与金属锂反应得到的电解质膜由高离子电导性的Li_(x)BO_(y), LiF, Li_(x)NO_(y), Li_(3)N颗粒及一些有机物构成,其中Li_(x)BO_(y)作为耦联剂可提高该膜的机械强度.有了这层保护膜之后,在DMI电解液中,锂沉积/剥离的库伦效率可从20%提高至98.5%,同时,组装的锂氧气电池在限容条件下进行循环,循环寿命长达205圈,几乎是二甲基亚砜(DMSO)或四乙二醇二甲醚(TEGDME)体系中的5倍.研究表明,分子极性和离子溶剂化结构是设计高性能锂-氧气电池电解质时要考虑的主要问题,而耦联的人工SEI可有效提高负极的稳定性.

关 键 词：1 3-Dimethyl-2-imidazolidinone Li-O2battery Solid state electrolyte Lithium anode 

分 类 号：TM911.41[电气工程—电力电子与电力传动] O646[理学—物理化学]