Abstract
High-voltage lithium metal batteries (LMBs) are promising for next-generation high-energy storage systems. Unfortunately, their implementation has been severely plagued by the interfacial instability between the high-voltage cathodes/lithium metal (LM) anodes and electrolytes. To tackle these challenges, a novel nitrile additive, 1,4-dicyanobenzene (DCB) (Synonyms: terephthalonitrile), is added to the in situ polymerized pentaerythritol tetraacrylate-based gel polymer electrolyte (GPE). The DCB additive, as demonstrated both theoretically and experimentally, plays a crucial role in altering the Li+ coordinated solvation structure within the GPE. This alteration leads to the formation of a pseudo-concentrated electrolyte with a tightly packed Li+ cluster, expanding the electrochemical stability window of the electrolyte. Moreover, the DCB-included GPE significantly improves its compatibility with both LM anode and high-voltage cathode, attributed to the modified solvation structure and the generated LiF-rich electrolyte/electrode interphases. Accordingly, the GPE enables stable cyclic performance of LMBs based on a 4.9 V LiNi0.5Mn1.5O4 cathode at a low relative negative/positive ratio of 4, achieving a high reversible capacity of 123.8 mAh g−1 with a capacity retention of 87.7 % over 500 cycles at 0.5 C. This work provides new insights into enhancing the cyclability of high-voltage LMBs via the synergistic effect of additives and GPE.
Original language | English |
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Article number | 103683 |
Journal | Energy Storage Materials |
Volume | 71 |
DOIs | |
State | Published - Aug 2024 |
Funding
This work is supported by the Natural Science Foundation of China ( 52277218 ), the Hubei Provincial Natural Science Foundation of China ( 2024AFA094 ) and the Excellent Discipline Cultivation Project by JHUN ( 2023XKZ009 ). The efforts Runming Tao and Jianlin Li contributed are completely independent and personal, which does not involve financial support from any funding agencies. The research of X.-G. S. was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under contract number DE-AC05-00OR22725 .
Keywords
- Gel polymer electrolyte
- High-voltage cathodes
- Li metal battery
- Li solvation structure
- Nitrile additive