Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, CH-8093, Switzerland.
Laboratory for Thin Films and Photovoltaics, Empa, Swiss Federal Laboratories for Materials Science & Technology, Dübendorf, CH-8600, Switzerland.
Adv Sci (Weinh). 2023 Mar;10(8):e2205821. doi: 10.1002/advs.202205821. Epub 2023 Jan 20.
Li dendrites form in Li La Zr O (LLZO) solid electrolytes due to intrinsic volume changes of Li and the appearance of voids at the Li metal/LLZO interface. Bilayer dense-porous LLZO membranes make for a compelling solution of this pertinent challenge in the field of Li-garnet solid-state batteries (SSB). Lithium is thus stored in the pores of the LLZO, thereby avoiding i) dynamic changes of the anode volume and ii) the formation of voids during Li stripping due to increased surface area of the Li/LLZO interface. The dense layer then additionally reduces the probability of short circuits during cell charging. In this work, a method for producing such bilayer membranes utilizing sequential tape-casting of porous and dense layers is reported. The minimum attainable thicknesses are 8-10 µm for dense and 32-35 µm for porous layers, enabling gravimetric and volumetric energy densities of Li-garnet SSBs of 279 Wh kg and 1003 Wh L , respectively. Bilayer LLZO membranes in symmetrical cell configuration exhibit high critical current density up to 6 mA cm and cycling stability of over 160 cycles at a current density of 0.5 mA cm at an areal capacity limitation of 0.25 mAh cm .
锂枝晶在 LiLaZrO(LLZO)固体电解质中形成,这是由于 Li 的固有体积变化和 Li 金属/LLZO 界面出现空隙。双层致密-多孔 LLZO 膜是解决 Li 石榴石固态电池(SSB)领域这一相关挑战的一个引人注目的解决方案。锂储存在 LLZO 的孔隙中,从而避免了:i)阳极体积的动态变化;ii)由于 Li/LLZO 界面表面积增加而在 Li 剥离过程中形成空隙。致密层还降低了电池充电过程中发生短路的可能性。在这项工作中,报道了一种利用多孔和致密层顺序涂覆制备这种双层膜的方法。致密层的最小可达厚度为 8-10μm,多孔层的最小可达厚度为 32-35μm,这使得 Li 石榴石 SSB 的重量和体积能量密度分别达到 279Whkg 和 1003WhL。在对称电池配置中,双层 LLZO 膜表现出高达 6mAcm的高临界电流密度和超过 160 次循环的循环稳定性,在 0.5mAcm的电流密度下,面积容量限制为 0.25mAhcm。