Boosting the Interfacial Stability of the Li6PS5Cl Electrolyte with a Li Anode via In Situ Formation of a LiF-Rich SEI Layer and a Ductile Sulfide Composite Solid Electrolyte

Gashahun Gobena Serbessa; Bereket Woldegbreal Taklu; Yosef Nikodimos; Nigusu Tiruneh Temesgen; Zabish Bilew Muche; Semaw Kebede Merso; Tsung-I Yeh; Ya-Jun Liu; Wei-Sheng Liao; Chia-Hsin Wang; She-Huang Wu; Wei-Nien Su; Chun-Chen Yang; Bing Joe Hwang

doi:10.1021/acsami.3c14763

Boosting the Interfacial Stability of the Li₆PS₅Cl Electrolyte with a Li Anode via In Situ Formation of a LiF-Rich SEI Layer and a Ductile Sulfide Composite Solid Electrolyte

ACS Appl Mater Interfaces. 2024 Feb 28;16(8):10832-10844. doi: 10.1021/acsami.3c14763. Epub 2024 Feb 15.

Authors

Gashahun Gobena Serbessa^{1

2}, Bereket Woldegbreal Taklu³, Yosef Nikodimos¹, Nigusu Tiruneh Temesgen¹, Zabish Bilew Muche¹, Semaw Kebede Merso¹, Tsung-I Yeh¹, Ya-Jun Liu¹, Wei-Sheng Liao³, Chia-Hsin Wang⁴, She-Huang Wu^{3

5}, Wei-Nien Su^{3

5}, Chun-Chen Yang^{2

6}, Bing Joe Hwang^{1

4

5}

Affiliations

¹ Nano-electrochemistry Laboratory, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei City 106, Taiwan.
² Battery Research Center of Green Energy, Ming-Chi University of Technology, New Taipei City 24301, Taiwan.
³ Nano-electrochemistry Laboratory, Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei City 106, Taiwan.
⁴ National Synchrotron Radiation Research Center (NSRRC), Hsinchu 30076, Taiwan.
⁵ Sustainable Electrochemical Energy Development (SEED) Center, National Taiwan University of Science and Technology, Taipei City 106, Taiwan.
⁶ Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan.

Abstract

Due to its good mechanical properties and high ionic conductivity, the sulfide-type solid electrolyte (SE) can potentially realize all-solid-state batteries (ASSBs). Nevertheless, challenges, including limited electrochemical stability, insufficient solid-solid contact with the electrode, and reactivity with lithium, must be addressed. These challenges contribute to dendrite growth and electrolyte reduction. Herein, a straightforward and solvent-free method was devised to generate a robust artificial interphase between lithium metal and a SE. It is achieved through the incorporation of a composite electrolyte composed of Li₆PS₅Cl (LPSC), polyethylene glycol (PEG), and lithium bis(fluorosulfonyl)imide (LiFSI), resulting in the in situ creation of a LiF-rich interfacial layer. This interphase effectively mitigates electrolyte reduction and promotes lithium-ion diffusion. Interestingly, including PEG as an additive increases mechanical strength by enhancing adhesion between sulfide particles and improves the physical contact between the LPSC SE and the lithium anode by enhancing the ductility of the LPSC SE. Moreover, it acts as a protective barrier, preventing direct contact between the SE and the Li anode, thereby inhibiting electrolyte decomposition and reducing the electronic conductivity of the composite SE, thus mitigating the dendrite growth. The Li|Li symmetric cells demonstrated remarkable cycling stability, maintaining consistent performance for over 3000 h at a current density of 0.1 mA cm^-2, and the critical current density of the composite solid electrolyte (CSE) reaches 4.75 mA cm^-2. Moreover, the all-solid-state lithium metal battery (ASSLMB) cell with the CSEs exhibits remarkable cycling stability and rate performance. This study highlights the synergistic combination of the in-situ-generated artificial SE interphase layer and CSEs, enabling high-performance ASSLMBs.

Keywords: dendrite suppression; in situ LiF generation; interfacial stability; lithium metal anode; solid-state battery; solvent-free solid sulfide composite electrolyte.