物理化学学报 >> 2021, Vol. 37 >> Issue (1): 2008065.doi: 10.3866/PKU.WHXB202008065

所属专题: 金属锂负极

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金属锂电池的热失控与安全性研究进展

张世超, 沈泽宇, 陆盈盈()   

  • 收稿日期:2020-08-22 录用日期:2020-09-16 发布日期:2020-09-21
  • 通讯作者: 陆盈盈 E-mail:yingyinglu@zju.edu.cn
  • 作者简介:陆盈盈,浙江大学化学与生物工程学院特聘研究员。于2010年获得浙江大学化学工程学士学位,2014年获得康奈尔大学博士学位。之后,在斯坦福大学材料科学与工程系担任博士后研究员。2015年入选国家海外高层次人才引进计划(青年项目),于2015年10月全职回浙江大学工作。主要研究方向包括纳米材料、电化学储能和转换
  • 基金资助:
    国家重点研发计划(2018YFA0209600);国家自然科学基金(21878268);浙江省引进领军型创新创业团队(2019R01006)

Research Progress of Thermal Runaway and Safety for Lithium Metal Batteries

Shichao Zhang, Zeyu Shen, Yingying Lu()   

  • Received:2020-08-22 Accepted:2020-09-16 Published:2020-09-21
  • Contact: Yingying Lu E-mail:yingyinglu@zju.edu.cn
  • About author:Yingying Lu. Email: yingyinglu@zju.edu.cn
  • Supported by:
    the National Key R & D Program of China(2018YFA0209600);the National Natural Science Foundation of China(21878268);the Leading Innovative and Entrepreneur Team Introduction Program ofZhejiang Province(2019R01006)

摘要:

锂离子电池在便携式储能器件及电动汽车领域得到了广泛应用,然而频繁发生的电池起火爆炸事故,使热失控和热安全问题备受人们关注,目前已有多篇综述报道了缓解锂离子电池热失控的措施。相比于已经接近理论比能极限的锂离子电池,金属锂负极具有更高的比容量、更低的电势和高反应活性,但是不可控的锂枝晶生长,使得金属锂电池的热失控问题更为复杂和严重。针对金属锂电池的热失控问题,本文首先介绍了热失控的诱因及基本过程和阶段,其次从材料层面综述了提高电池热安全性的多种策略,包括使用阻燃性电解质、离子液体电解质、高浓电解质和局域高浓电解质等不易燃液态电解质体系,开发高热稳定性隔膜、热响应隔膜、阻燃性隔膜和具有枝晶检测预警与枝晶消除功能的新型智能隔膜,以及研究热响应聚合物电解质,最后对金属锂电池热失控在未来的进一步研究进行了展望。

关键词: 热失控, 热安全, 金属锂负极, 金属锂电池

Abstract:

Lithium ion batteries have been widely used in the fields of portable energy storage devices and electric vehicles due to their high energy density and high safety, and have a profound impact on modern society. However, the frequent occurrence of battery fire and explosion accidents has caused widespread concern of thermal runaway and thermal safety issues. Many reviews have reported the measures to mitigate thermal runaway of lithium ion batteries. Due to the use of graphite with a smaller capacity as the negative electrode material, the specific energy of lithium ion batteries has approached the theoretical limit, and there is an urgent need to develop more efficient electrode materials to meet the growing demand of the energy storage market. Lithium metal anode has smaller density, higher theoretical capacity and lower potential, which is the ideal anode material for the next generation of high energy density battery system. However, the high reactivity of lithium will cause uncontrollable lithium dendrite growth during the cycle, which may penetrate the separator and cause internal short circuit of the battery, and then cause thermal runaway, fire and even explosion. Therefore, the thermal runaway of lithium metal batteries are more complicated and serious, which hinders the commercial application of batteries. Aiming at the thermal runaway problem of lithium metal batteries, this article first introduces the causes of thermal runaway, which are mainly uncontrollable exothermic reactions caused by internal short circuits. The basic process of thermal runaway is divided into three stages. By analyzing the three characteristic temperatures and heating rate, it is proved that improving the thermal stability of electrolyte and seperator can alleviate thermal runaway. Then we investigated the influence of thermodynamics on the nucleation and growth of lithium dendrites, revealing the dual effects of temperature, and proving that a uniform thermal field is beneficial to obtain uniform lithium deposition and improve battery cycle performance and safety. Secondly, a variety of strategies to improve battery thermal safety are reviewed at the material level. In terms of liquid electrolytes, the development of non-flammable electrolyte systems includes the use of flame-retardant electrolytes and ionic liquid electrolytes with lower flammability. In addition, high-concentration electrolyte and local high-concentration electrolyte can change the solvation structure of lithium ions, and improve safety by reducing the number of free solvent molecules. In terms of separators, high thermal stability separators and thermal response separators with thermal shutdown function have been developed. The flame-retardant separators can release flame retardants to inhibit combustion. In addition, the new intelligent separators have dendrite detection, early warning and elimination functions, which effectively improve the safety and cycle life of the battery. In terms of solid electrolytes, thermally responsive polymer electrolytes have been developed to avoid thermal runaway through the strain function of polymer materials. Finally, further research on the thermal runaway of lithium metal batteries in the future is prospected.

Key words: Thermal runaway, Thermal safety, Lithium metal anode, Lithium metal battery

MSC2000: 

  • O646