摘要
Densified garnet-type Li <sub>6.4</sub> La <sub>3</sub> Zr <sub>1.4</sub> Ta <sub>0.6</sub> O <sub>12</sub> (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 <sup>−5</sup> -10 <sup>−4</sup> to 10 <sup>−4</sup> -10 <sup>−3</sup> S cm <sup>−1</sup> . 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 <sup>−1</sup> 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 <sup>−1</sup> and short cycle life of <50 cycles during charging–discharging at 0.1C.