摘要
The garnet-type electrolyte is one of the most promising solid-state electrolytes(SSEs)due to its high ionic conductivity(σ)and wide electrochemical window.However,such electrolyte generates lithium carbonate(Li_(2)CO_(3))in air,leading to an increase in impedance,which greatly limits their practical applications.In turn,high-entropy ceramics(HECs)can improve phase stability due to high-entropy effect.Herein,high-entropy garnet(HEG)Li_(6.2)La_(3)(Zr_(0.2)Hf_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(12)(LL(ZrHfTiNbTa)O)SSEs were synthesized by the solid-state reaction method.X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),electrochemical impedance spectroscopy(EIS),and scanning electron microscopy(SEM)characterizations indicated that the LL(ZrHfTiNbTa)O electrolyte has excellent air stability.Room-temperature conductivity of LL(ZrHfTiNbTa)O can be maintained at~1.42×10^(-4)S/cm after exposure to air for 2 months.Single-element-doped garnets were synthesized to explain the role of different elements and the mechanism of air stabilization.In addition,a lithium(Li)/LL(ZrHfTiNbTa)O/Li symmetric cell cycle is stable over 600 h,and the critical current density(CCD)is 1.24 mA/cm^(2),indicating remarkable stability of the Li/LL(ZrHfTiNbTa)O interface.Moreover,the LiFePO_(4)/LL(ZrHfTiNbTa)O/Li cell shows excellent rate performance at 30℃.These results suggest that HECs can be one of the strategies for improving the performance of SSEs in the future due to their unique effects.
基金
funded by the Central Government Guides Local Science and Technology Development Special Fund Projects(Grant No.YDZJSX2022B003)
the Shanxi Province Science and Technology Major Projects(Grant No.202101120401008)
the Key Research and Development Project of Shanxi Province(Grant No.202102030201006)
Science and Technology Activities of Overseas Students Merit-based Funding Projects of Shanxi Province(Grant No.2021037).
