Zettl Roman, de Kort Laura, Gombotz Maria, Wilkening H Martin R, de Jongh Petra E, Ngene Peter
Institute for Chemistry and Technology of Materials, and Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (NAWI Graz), Stremayrgasse 9, 8010 Graz, Austria.
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, Netherlands.
J Phys Chem C Nanomater Interfaces. 2020 Feb 6;124(5):2806-2816. doi: 10.1021/acs.jpcc.9b10607. Epub 2020 Jan 21.
Solid-state electrolytes are crucial for the realization of safe and high capacity all-solid-state batteries. Lithium-containing complex hydrides represent a promising class of solid-state electrolytes, but they exhibit low ionic conductivities at room temperature. Ion substitution and nanoconfinement are the main strategies to overcome this challenge. Here, we report on the synthesis of nanoconfined anion-substituted complex hydrides in which the two strategies are effectively combined to achieve a profound increase in the ionic conductivities at ambient temperature. We show that the nanoconfinement of anion substituted LiBH (LiBH-LiI and LiBH-LiNH) leads to an enhancement of the room temperature conductivity by a factor of 4 to 10 compared to nanoconfined LiBH and nonconfined LiBH-LiI and LiBH-LiNH, concomitant with a lowered activation energy of 0.44 eV for Li-ion transport. Our work demonstrates that a combination of partial ion substitution and nanoconfinement is an effective strategy to boost the ionic conductivity of complex hydrides. The strategy could be applicable to other classes of solid-state electrolytes.
固态电解质对于实现安全且高容量的全固态电池至关重要。含锂复合氢化物是一类很有前景的固态电解质，但它们在室温下表现出较低的离子电导率。离子取代和纳米限域是克服这一挑战的主要策略。在此，我们报告了纳米限域阴离子取代复合氢化物的合成，其中这两种策略有效地结合在一起，实现了室温下离子电导率的显著提高。我们表明，与纳米限域的LiBH以及非限域的LiBH-LiI和LiBH-LiNH相比，阴离子取代的LiBH（LiBH-LiI和LiBH-LiNH）的纳米限域导致室温电导率提高了4至10倍，同时锂离子传输的活化能降低至0.44 eV。我们的工作表明，部分离子取代和纳米限域相结合是提高复合氢化物离子电导率的有效策略。该策略可能适用于其他类别的固态电解质。
