Lithium-metal batteries (LMBs) are good candidates for next-generation energy-storage systems due to their ultrahigh theoretical capacity. However, their practical application is hindered by safety issues: The formation of lithium dendrites during repeated charge/discharge processes can result in short circuits or even explosions.
Yunsheng Ye, Huazhong University of Science and Technology, Wuhan, China, and colleagues have developed a new class of quasi-solid-state electrolyte (QSSE) for safer LMBs. The electrolyte consists of an ionic-liquid functional covalent triazine-based framework (IL-fCTF, pictured below) and a lithium-based ionic liquid (LIL, pictured below). The covalent framework was synthesized using a low‐temperature polycondensation approach, followed by a nucleophilic N-alkylation. The framework was then mixed with the LIL, which consists of LiTFSI and [Bmim][TFSI] (TFSI = bis(trifluoromethane)sulfonimide, Bmim = 1‐butyl‐3‐methylimidazolium), to obtain the desired QSSE.
The team used the developed QSSE in LMBs, which showed high room-temperature ionic conductivity, good cycling stability, and good rate capacity. The electrolyte improves the safety of LMBs due to the near-total resistance to Li dendrite growth caused by its robust skeleton, as well as the use of non-flammable ionic liquids. These results show the promise of porous organic polymeric materials for energy-storage systems.
- Functional Covalent Triazine Frameworks-Based Quasi-Solid-State Electrolyte Used to Enhance Lithium Metal Battery Safety,
Qing Xuan Shi, Xin Guan, Hui Jie Pei, Chen Chang, Hao Qu, Xiao Lin Xie, Yun Sheng Ye,
Batteries Supercaps 2020.