Tailoring Electrolyte Solvation for LiF-Rich Solid Electrolyte Interphase toward a Stable Li Anode

Haifeng Tu; Linge Li; Zhicheng Wang; Jian Wang; Hongzhen Lin; Mingchao Wang; Cheng Yan; Meinan Liu

doi:10.1021/acsnano.2c06924

Tailoring Electrolyte Solvation for LiF-Rich Solid Electrolyte Interphase toward a Stable Li Anode

ACS Nano. 2022 Oct 25;16(10):16898-16908. doi: 10.1021/acsnano.2c06924. Epub 2022 Sep 28.

Authors

Haifeng Tu^{1

2}, Linge Li³, Zhicheng Wang³, Jian Wang³, Hongzhen Lin³, Mingchao Wang⁴, Cheng Yan⁵, Meinan Liu^{1

3

6}

Affiliations

¹ Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China.
² Nano Science and Technology Institute, University of Science and Technology of China, Hefei, Anhui 230026, China.
³ School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, Anhui 230026, China.
⁴ Centre for Theoretical and Computational Molecular Science, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia.
⁵ School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia.
⁶ Division of Nanomaterials and Jiangxi Key Lab of Carbonene Materials, Jiangxi Institute of Nanotechnology, Nanchang 330200, China.

PMID: 36169299
DOI: 10.1021/acsnano.2c06924

Abstract

A solid electrolyte interphase (SEI) with robust mechanical property and high ionic conductivity is imperative for high-performance lithium metal batteries since it can efficiently impede the growth of notorious lithium dendrites. However, it is difficult to form such a SEI directly from an electrolyte. In this work, a crowding dilutant modified ionic liquid electrolyte (M-ILE) has been developed for this purpose. Simulations and experiments indicate that the 1,2-difluorobenzene (1,2-dfBen) dilutant not only creates a crowded electrolyte environment to promote the interaction of Li⁺-FSI^-, leading to abundant aggregate ion pairs (AGGs), but also participates in the reduction to construct a robust and high ionic-conductive SEI. With this M-ILE, Li/LiFePO₄ cells achieve a capacity retention of 96% over 250 cycles with 9.5 mg cm^-2 mass loading, and Li/LiNi_0.5Co_0.2Mn_0.3O₂ cells also deliver a discharge capacity of 132 mAh g^-1 with a high retention of 88% after 100 cycles. Therefore, the use of a crowding diluent is considered to be an efficient way to construct an advanced SEI for a Li anode.

Keywords: crowding dilutant; ionic liquid electrolytes; lithium metal battery; solid electrolyte interphase; solvation structure.