Interfacial Ion‐Transport Mechanism of Li7(Al0.1)La3Zr2O12 Solid Electrolyte Modified by using a Spark Plasma Sintering Method. Issue 24 (25th October 2018)

• Record Type: Journal Article
• Authors: Bai, Lixiong; Xue, Wendong; Xue, Yawen; Qin, Haixia; Li, Yan; Li, Yong; Sun, Jialin
• Is Part Of: ChemElectroChem. Volume 5:Issue 24(2018)
• Page Start: 3918
• Page End: 3925
• Publication Date: 2018-10-25
• Subjects: interfacial impedance -- ion transport -- migration barrier -- solid electrolytes -- spark plasma sintering; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201801229
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: A novel interfacial in situ modification for Li7 (Al0.1 )La3 Zr2 O12 is designed and prepared by using a spark plasma sintering method. The modified interface with most grain boundary area exhibits excellent interfacial electrochemical properties. The X‐ray diffraction (XRD) and scanning electron microscope (SEM) data indicate that the interfacial modified specimen (spark plasma sintering method, 1000 °C, 5 min) with 38.2(6) nm grain diameter and 32, 134 cm 2 /g grain boundary specific surface area has the highest ionic conductivity (8.84×10 −4 S/cm −1 ). The lithium‐ion transmission mechanism in grain‐internal and grain boundaries is revealed by ab initio theory, using Materials Studio software. Furthermore, the first‐principles calculation data indicate that the migration barrier of Li + at the Li7 (Al0.1 )La3 Zr2 O12 solid electrolyte grain boundary is 0.21 eV, which is only 2/3 of that in the grain internal (0.33 eV). As a result, SPS interfacial in situ processing technology can increase the grain boundary area, thereby reducing the ion transport barrier and the interfacial impedance of the material. Abstract : Choosing the right path : When a voltage is applied on both sides of an all‐solid‐state lithium‐ion battery, the ions at the grain boundary have two migration paths. The increase of grain boundary area promotes the Li migration and reduces the activation energy of the electrolyte. A higher Li + concentration can increase the diffusion coefficient of Li + in the crystal structure, which also accelerates the diffusion coefficient of Li + in the solid electrolyte.