Ji Hu, Alexander G. Squires, Jędrzej Kondek, Michael J. Johnson, Arthur B. Youd, Pooja Vadhva, Partha P. Paul, Philip J. Withers, Marco Di Michiel, Dean S. Keeble, Michael Ryan Hansen, David O. Scanlon and Alexander J. E. Rettie
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引用次数: 0
Abstract
Lithium phosphides are an emerging class of Li+ ion conductors for solid state battery applications. Despite potentially favorable characteristics as a solid electrolyte, stoichiometric crystalline Li3AlP2 has been reported to be an ionic insulator. Using a combined computational and experimental approach, we investigate the underlying reasons for this and show that ion transport can be induced via defects and structural disorder in this material. Lithium vacancies are shown to promote diffusion, and a low barrier to Li+ hopping of 0.2–0.3 eV is revealed by both simulations and experiment. However, polycrystalline pellets exhibit low ionic conductivity (≈10−8 S cm−1) at room temperature, attributed to crystalline anisotropy and the presence of resistive grain boundaries. These aspects can be overcome in nanocrystalline Li3AlP2, where ionic conductivity values approaching 10−6 S cm−1 and low electronic conductivities are achieved. This approach, leveraging both defects and structural disorder, should have relevance to the discovery of new, or previously overlooked, ion conducting materials.
磷化锂是一类新兴的锂离子导体,用于固态电池的应用。尽管作为固体电解质具有潜在的有利特性,但化学计量晶体Li3AlP2已被报道为离子绝缘体。使用计算和实验相结合的方法,我们研究了这种情况的潜在原因,并表明离子传输可以通过这种材料中的缺陷和结构紊乱诱导。模拟和实验均表明,锂空位有利于扩散,且对Li+跃迁具有0.2 ~ 0.3 eV的低势垒。然而,由于晶体各向异性和电阻晶界的存在,多晶颗粒在室温下表现出低离子电导率(≈10−8 S cm−1)。这些方面可以在纳米晶Li3AlP2中克服,其中离子电导率值接近10−6 S cm−1,并且实现了低电子电导率。这种利用缺陷和结构紊乱的方法,应该与发现新的或以前被忽视的离子导电材料有关。
期刊介绍:
The Journal of Materials Chemistry A, B & C covers a wide range of high-quality studies in the field of materials chemistry, with each section focusing on specific applications of the materials studied. Journal of Materials Chemistry A emphasizes applications in energy and sustainability, including topics such as artificial photosynthesis, batteries, and fuel cells. Journal of Materials Chemistry B focuses on applications in biology and medicine, while Journal of Materials Chemistry C covers applications in optical, magnetic, and electronic devices. Example topic areas within the scope of Journal of Materials Chemistry A include catalysis, green/sustainable materials, sensors, and water treatment, among others.