A solid-liquid composite electrolyte with a vertical microporous [formula omitted] skeleton that prepared by femtosecond laser structuring and filled with ionic liquid

Abstract

We report a novel composite electrolyte, composed of ceramic Li1.5Al0.5Ge1.5(PO4)3 (LAGP) skeleton with tunable vertical pores and ionic liquids (IL) fillers. both components have high-safety features. The vertical ionic liquid channels that prepared by femtosecond laser shorten the lithium ion transport path and the ionic liquid on the electrolyte surface improves the wettability between the solid electrolyte and electrode material. The total impedance of the pores LAGP&IL electrolytes (PLI) is 411.6 Ω，with the ionic conductivity of 4.3 × 10−5 S/cm at room temperature. Compared with non-pores LAGP&IL electrolytes (NPLI), the total impedance is reduced by 3 times. The lithium ion transference number of PLI electrolyte is 0.53, which is in contrast to the value 0.29 of NPLI electrolyte. The full cell consisting of LiFePO4 (LFP) | composite electrolyte | Li demonstrates a specific capacity of 136.6 mAhg−1 on the first cycle of discharge at 0.1C and a capacity retention rate of 89.7% after 20 cycles at room temperature. The symmetrical battery can cycle stably for 60 h at room temperature, which is 140% longer than that of non-pores LAGP composite ionic liquid electrolyte. This work provides an insight into the high-performance electrolyte preparation and its significance in the high-safety lithium-metal battery.