Ultrathin, Mechanically Robust Quasi-Solid Composite Electrolyte for Solid-State Lithium Metal Batteries

Qingrong Wang; Hongli Xu; Zhongbo Liu; Shang-Sen Chi; Jian Chang; Jun Wang; Chaoyang Wang; Yonghong Deng

doi:10.1021/acsami.4c01426

Ultrathin, Mechanically Robust Quasi-Solid Composite Electrolyte for Solid-State Lithium Metal Batteries

ACS Appl Mater Interfaces. 2024 May 1;16(17):22482-22492. doi: 10.1021/acsami.4c01426. Epub 2024 Apr 23.

Authors

Qingrong Wang¹, Hongli Xu¹, Zhongbo Liu², Shang-Sen Chi¹, Jian Chang³, Jun Wang¹, Chaoyang Wang⁴, Yonghong Deng¹

Affiliations

¹ Department of Materials Science and Engineering, School of Innovation and Entrepreneurship, Guangdong Provincial Key Laboratory of Energy Materials for Electric Power, Southern University of Science and Technology, Shenzhen 518055, PR China.
² Shenzhen CAPCHEM Technology Co. Ltd., Shabo Tongfuyu Industry Zone, Pingshan New District, Shenzhen 518118, PR China.
³ School of Physical Sciences, Great Bay University, Dongguan 523000, PR China.
⁴ Research Institute of Materials Science, South China University of Technology, Guangzhou 510640, PR China.

PMID: 38651802
DOI: 10.1021/acsami.4c01426

Abstract

Herein, we present the preparation and properties of an ultrathin, mechanically robust, quasi-solid composite electrolyte (SEO-QSCE) for solid-state lithium metal battery (SLB) from a well-defined polystyrene-b-poly(ethylene oxide) diblock copolymer (SEO), Li_6.75La₃Zr_1.75Ta_0.25O₁₂ nanofiller, and fluoroethylene carbonate plasticizer. Compared with the ordered lamellar microphase separation of SEO, the SEO-QSCE displays bicontinuous phases, consisting of a Li⁺ ion conductive poly(ethylene oxide) domain and a mechanically robust framework of the polystyrene domain. Therefore, the 12 μm-thick SEO-QSCE membrane exhibits an exceptional ionic conductivity of 1.3 × 10^-3 S cm^-1 at 30 °C, along with a remarkable tensile strength of 5.1 MPa and an elastic modulus of 2.7 GPa. The high mechanical robustness and the self-generated LiF-rich SEI enable the SEO-QSCE to have an extraordinary lithium dendrite prohibition effect. The SLB of Li|SEO-QSCE|LiFePO₄ reveals superior cycling performances at 30 °C for over 600 cycles, maintaining an initial discharge capacity of 145 mAh g^-1 and a remarkable capacity retention of 81% (117 mAh g^-1) after 400 cycles at 0.5 C. The high-voltage SLB of Li|SEO-QSCE|LiNi_0.5Co_0.3Mn_0.2O₂ displays good cycling stability for over 150 cycles at 30 °C. Moreover, the exceptional robustness of SEO-QSCE enables the high-voltage solid-state pouch cell of Li|SEO-QSCE|LiNi_0.5Co_0.3Mn_0.2O₂ with high flexibility and excellent safety features. The current investigation delivers a promising and innovative approach for preparing quasi-solid electrolytes with features of ultrathin design, mechanical robustness, and exceptional electrochemical performance for high-voltage SLBs.

Keywords: bicontinuous phase; lithium metal battery; polystyrene-b-poly(ethylene oxide) diblock copolymer; quasi-solid composite electrolyte; ultrathin.