Due to its high energy density and better safety performance, all-solid-state lithium batteries are regarded as important energy storage devices to replace the traditional liquid electrolyte Li-ion batteries. However, the problems of poor wettability of Li metal anode | solid-state electrolyte interface and easy growth of lithium dendrite have not been well solved. Here, we have constructed Fe-doped Li 7-3x Fe x La 3 Zr 2 O 12 (Fe-LLZO) and Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) garnet-type double-layer solid electrolyte. The high density of Li 7-3x Fe x La 3 Zr 2 O 12 electrolyte and its interfacial wettability to Li metal not only effectively reduced the interface impedance between Li and solid electrolyte but also could stably cycle for more than 200 h without the growth of lithium dendrites at the rate of 0.1 mA cm −2 . In addition, the all-solid-state lithium battery (Li|Fe 0.1 -LLZO|LLZTO|LFP) with LiFePO 4 as a cathode also showed excellent cycle stability and C-rate performance.
Xueting Yang,Dezhan Ye,Chenyi Wang,Yazhou Chen,Xiancai Jiang,Yingcheng Yang,Zengjin Liu
The emerging approach of in-situ polymerization of solid polymer electrolytes based on 1,3-dioxolane (DOL) possesses the advantage of low interfacial impedance and relatively high Coulombic efficiency. However, the DOL monomer conversion (C%) under Lewis acid catalysts needs to be further improved, besides their alloying ability with lithium metal to generate protective interfacial layer has been ignored. Here, the above two aims are simultaneously achieved by Indium Trifluoride (InF 3 ) catalyst. It is demonstrated that the highest C% is up to 94% with 15 mg of InF 3 in the 1 mL electrolyte (1 M LiTFSI/DOL). The optimized ionic conductivity and lithium-ion transfer number are 8.9 × 10 −5 S/cm (30 °C) and 0.42, respectively. The stable interface between poly-DOL and lithium metal anode could be proved by the stable over-potential (156mv, 900 h) at current density of 2.0 mA cm −2 . X-ray diffraction results confirm the presence of In and In–Li alloy peaks. After 300 cycles at 1C, the assembled Li/PDI 15 /LiFePO 4 cells deliver a 125.2mAh/g, 90% capacity retention and Coulombic efficiency of 99.75%, respectively. This innovative and facile strategy of dual functional InF 3 on the in-situ polymerization of DOL and solid electrolyte interphase formation provides new ideas for design poly-DOL based solid polymer electrolytes.
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