摘要
Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss.Here,we report a composite Li anode composed(LYF)of metallic Li and trace amounts(1 e2 wt%)of two-dimensional YF_(δ).The lithiophilic nature of YF_(δ) enables its homogeneous dispersion in metallic lithium.The LYF electrode exhibits lower resistance,higher chemical and mechanical stability,and longer cycle life compared to bare Li electrode due to uniform Li stripping and plating with YF_(δ) incorporation,which was confirmed by in-situ optical microscope observation.X-ray photoelectron spectroscopy reveals that LiF can in-situ form on the LYF electrode with reactions between Li and YF_(δ) during cycling.The spontaneous reactions are clarified by density functional theory calculations.A quasisolid-state cell with LYF anode,LiFePO_(4) cathode and cathode-supported solid electrolyte layer has been constructed with a soft interface constructed between Li anode and solid electrolyte by in-situ thermal polymerization.The cell shows a high initial discharge capacity of 147 mAh g1 at 0.5℃ at 60℃ and sustains a stable cycling over 50 cycles with the in-situ formed LiF-rich layer and soft interface.
基金
supported by the National Natural Science Foundation of China(Grant no.51572238,51725102)
and Zhejiang Provincial Natural Science Foundation of China(Grant no.LY19E020013).
