Sn掺杂石榴石型Li_(7)La_(3)Zr_(2)O_(12)固态电解质的制备

Preparation of Sn-doped Li_(7)La_(3)Zr_(2)O_(12)Garnet Solid Electrolyte

锂离子电池中的液态电解质存在易燃、易爆等问题,固态电解质因具有较高安全性和稳定性成为潜在的替代品。在众多无机固态锂离子电解质中,Li_(7)La_(3)Zr_(2)O_(12)(LLZO)电解质材料的晶粒电导率和晶界电导率相当,在提高电导率和稳定性等方面具有很大的发展前景。为了进一步提高该材料的导电性,采用固相法将SnO_(2)掺杂到LLZO中,通过XRD、交流阻抗和离子活化能等测试研究了不同掺杂量对LLZO电导率的影响。未掺杂的Li_(7)La_(3)Zr_(2)O_(12)的离子电导率为2.58×10^(-6)S/cm,由于Sn^(4+)的掺杂稳定了LLZO的立方相,随着Sn^(4+)掺杂量增加到0.3时,即Li_(7)La_(3)Zr_(1.7)Sn_(0.3)O_(12),其离子电导率达到了2.52×10^(-5)S/cm,使LLZO材料的电导率提高了一个数量级。

The liquid electrolytes in lithium ion batteries have serious problems,such as high flammability and possible explosion.Solid electrolytes are potential replacements for the liquid electrolytes,due to their high safety and stability.Among various inorganic solid lithium ion electrolytes,Li_(7)La_(3)Zr_(2)O_(12)(LLZO)based electrolyte possesses bulk conductivity and grain boundary conductivity comparable with those of the liquid electrolytes,thus having great prospects in terms of improving conductivity and stability.In order to further improve its conductivity,LLZO was doped with SnO_(2) through the conventional ceramic processing.The LLZO samples were characterized by using XRD and AC impedance,while the ion activation energy was derived.The ionic conductivity of pure Li_(7)La_(3)Zr_(2)O_(12) is 2.58×10^(-6) S/cm.The doping with Sn4+stabilized the cubic phase of LLZO.The sample(Li_(7)La_(3)Zr_(1.7)Sn_(0.3)O_(12))with 0.3 Sn^(4+)had an ionic conductivity of 2.52×10^(-5) S/cm,which is higher than that of pure LLZO by about one order of magnitude.