1,2,3,4-Tetrakis(2-cyanoethoxy)butane (TCEB)-Assisted Construction of Self-Repair Electrode Interface Films to Improve the Performance of 4.5 V Pouch LiCoO2/Artificial Graphite Full Cells Operating at 45 °C

• Published in: ACS applied materials & interfaces 2021-12, Vol.13 (50), p.59925-59936
• Main Authors: Wang, Wenlian, Zeng, Xueyi, Hu, Huilin, Yang, Tianxiang, Ma, Zhen, Fan, Weizhen, Zhao, Xiaoyang, Fan, Chaojun, Zuo, Xiaoxi, Nan, Junmin
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c18252

1,2,3,4-Tetrakis­(2-cyanoethoxy)­butane (TCEB) is first evaluated as a functional electrolyte additive to increase the charge cutoff voltage and energy density of pouch LiCO2 (LCO)/artificial graphite (AG) lithium-ion batteries (LIBs) at a high temperature of 45 °C. The charge (0.7 C) and discharge (1 C) tests show that TCEB effectively improves the cycle stability of cells under a high charge cutoff voltage of 4.5 V. At 25 °C, the capacity retention of the cells with TCEB increases from 0.0% to 72.1% after 1200 cycles. At 45 °C, the capacity retention of the cells without TCEB after 50 cycles is close to 0.0%, while the capacity retention of the cells with TCEB is still 81.6%, even after 350 cycles. The spectroscopic characterization results demonstrate that the TCEB electrolyte additive participates in the construction of a self-repair electrode/electrolyte interface film. Subsequently, low impedance and strong protective layers are formed on the two electrode surfaces. The quantitative analysis results and a theoretical calculation also show that TCEB effectively inhibits the dissolution of Co3+ and maintains the structural integrity of electrode materials. These results indicate that TCEB endows LIBs with excellent cycle stability and is a promising electrolyte additive for the high-voltage and high-temperature conditions of LCO-based LIBs.