High Li ion conductivity in a garnet-type solid electrolyte via unusual site occupation of the doping Ca ions
High Li ion conductivity in a garnet-type solid electrolyte via unusual site occupation of the doping Ca ions
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DOI：
10.1016/j.matdes.2015.12.149
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发表时间：
2016-03-05
影响因子：
8.4
通讯作者：
Lu, Li
中科院分区：
文献类型：
--
作者：
Song, Shufeng;Sheptyakov, Denis;Lu, Li
寻找具有高稳定性和离子电导率的固体电解质是开发安全和高能量密度锂离子电池的长期追求的目标。石榴石型锂导体由于其良好的化学稳定性而成为最有前途的材料家族。然而，室温下的低电导率阻碍了这些材料的更广泛应用。人们早已认识到碱土金属仅局限于石榴石骨架内的十二面体 8 配位位点。与这一主流观点相反，我们发现Ca2+阳离子可以占据八面体6配位位点，从而使室温电导率提高5.2 x 10(-4) S cm(-1)，活化能降低0.27 eV，并具有0至9 V的电化学稳定性窗口。这一发现为设计具有更高电导率的陶瓷电解质开辟了新的机会，为进一步探索氧化物电解质化学提供了额外的动力。 (C) 2015 Elsevier Ltd. 保留所有权利。
The search for solid electrolytes with high stability and ionic conductivity is a long sought-after goal in the development of safe and high energy density Li-ion batteries. Garnet-type lithium conductors form a most promising family of materials due to their good chemical stability. However, the low conductivity at room temperature prevents wider application of these materials. It has long been recognized that alkaline earth metals are confined exclusively to dodecahedral 8-coordinated sites within the garnet framework. In contrast to this dominant viewpoint, we show that Ca2+ cations can occupy the octahedral 6-coordinated sites, leading to an enhanced room temperature conductivity of 5.2 x 10(-4) S cm(-1) and reduced activation energy of 0.27 eV, together with a 0 to 9 V electrochemical stability window. This finding opens up a new opportunity for the design of ceramic electrolytes with higher conductivities, providing added impetus for further exploration of oxide electrolyte chemistry. (C) 2015 Elsevier Ltd. All rights reserved.