(376av) Mechanistic Insights into Electrolyte Stability Toward Li/Na Anodes

Lithium (Li) and sodium (Na) metal batteries are considered as
promising next-generation energy storage devices due to their ultrahigh energy
densities. However, the high reactivity of alkali metal toward organic solvents
and salts renders inevitable side reactions, which further leads to undesirable
electrolyte depletion, cell failure, and evolution of flammable gas. A novel
multiscale calculation, in combination with in situ optical microscopic
observations, was applied to investigate the intrinsic instability of normal
organic electrolytes (PC, DOL, DME, and TEGDME) towards Li and Na metal anodes.
Once complexed with Li/Na ions, solvent molecules exhibit a significantly
reduced the lowest unoccupied molecular orbital level, facilitating the
electrolyte decomposition and gas evolution. Based on this mechanistic insight,
novel strategies are proposed to build a stable Li/Na anode-electrolyte
interphase and thus long-life safe Li/Na metal batteries.

Fig. 1. Comparisons among the LUMO levels of
pure solvent and ion-solvent complexes.

Reference:
[1] Chen, X.; Shen, X.; Li, B.; Peng,
H. J.; Cheng, X. B.; Li, B. Q.; Zhang, X. Q.; Huang, J. Q.; Zhang, Q. Angew.
Chem. Int. Ed. 2018, 57: 734¨C737.

[2] Chen, X.; Hou, T. Z.; Li, B.; Yan,
C.; Zhu, L.; Guan, C.; Cheng, X. B.; Peng, H. J.; Huang, J. Q.; Zhang, Q. Energy
Storage Mater. 2017, 8:
194¨C201.

[3] Zhang, X. Q.;
Chen, X.; Xu, R.; Cheng, X. B.; Peng, H. J.; Zhang, R.; Huang, J. Q.; Zhang Q. Angew.
Chem. Int. Ed. 2017, 56: 14207¨C14211.

[4] Zhang, X. Q.; Cheng, X.-B.; Chen,
X.; Yan, C.; Zhang Q. Adv. Funct. Mater. 2017, 27:
1605989.

[5] Zhang, R.;
Chen, X. R.; Chen, X.; Cheng, X. B.; Zhang, X. Q.; Yan, C.; Zhang, Q. Angew.
Chem. Int. Ed. 2017, 56: 7764¨C7768.

[6]. Cheng, X. B.; Yan, C.; Chen, X.; Guan, C.; Huang, J.
Q.; Peng, H. J.; Zhang, R.; Yang, S. T.; Zhang, Q. Chem 2017, 2: 258¨C270.