Liquid metallic Ga as sintering aid to promote the densification of garnet electrolytes for all-solid-state Li-ion batteries

• Published in: Journal of power sources Vol. 556; p. 232527
• Main Authors: Huang, Ling-Hsuan, Li, Chia-Chen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023
• Subjects: Ceramic; Electrolyte; Garnet; Li-ion battery; Liquid metallic Ga; LLZTO; Garnet; Ceramic; Electrolyte; Li-ion battery; LLZTO; Liquid metallic Ga
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2022.232527

Densified garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) ceramic sheets with a thickness of 135 ± 5 μm and relative density of >97% are prepared and used as electrolytes for all-solid-state lithium iron phosphate (LFP) batteries. Liquid metallic Ga (LM-Ga) helps to densify the LLZTO sheet at a low sintering temperature (1050 °C) over a short firing time (3 h). The addition of LM-Ga to LLZTO does not increase the electronic conductivity of the electrolyte; however, it improves the densification and surface flatness of LLZTO. Moreover, it increases the ionic conductivity of LLZTO from 10−5-10−4 to 10−4-10−3 S cm−1. The mechanisms promoting the densification of LLZTO via the addition of LM-Ga are clarified and discussed. The charge–discharge capacities of the LFP battery assembled using LM-Ga–added LLZTO as the electrolyte are 150 and > 100 mAh g−1 at 0.1 and 0.6C, respectively, and a cycle life of at least 100 cycles at 0.1C. In contrast, the battery assembled using bare LLZTO as the electrolyte presents a capacity of <140 mAh g−1 and short cycle life of <50 cycles during charging–discharging at 0.1C. [Display omitted] •Densified LLZTO electrolyte sheets are achieved by sintering at 1050 °C for 3 h.•Liquid metallic Ga is an effective sintering aid for densifying LLZTO electrolytes.•The densified LLZTO electrolytes are used for all-solid-state LFP batteries.•The all-solid-state LFP battery presents a cycle life of at least 100 cycles at 0.1C.