Among all-solid-state batteries, rechargeable Al-ion batteries have attracted most attention because they involve threeelectron-redox reactions with high theoretic specific capacity. However, the solid Al-ion conducto...Among all-solid-state batteries, rechargeable Al-ion batteries have attracted most attention because they involve threeelectron-redox reactions with high theoretic specific capacity. However, the solid Al-ion conductor electrolytes are less studied. Here, the microscopic path of Al3+-ion conduction of NASICON-type(Al0.2Zr0.8)20/19Nb(PO4)3oxide is identified by temperature-dependent neutron powder diffraction and aberration-corrected scanning transmission electron microscopy experiments.(Al0.2Zr0.8)20/19Nb(PO4)3shows a rhombohedral structure consisting of a framework of(Zr,Nb)O6octahedra sharing corners with(PO4) tetrahedra; the Al occupy trigonal antiprisms exhibiting extremely large displacement factors. This suggests a strong displacement of Al ions along the c axis of the unit cell as they diffuse across the structure by a vacancy mechanism. Negative thermal expansion behavior is also identified along a and b axes, due to folding of the framework as temperature increases.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51672029,51372271,and 51172275)the National Key Research and Development Project from the Ministry of Science and Technology,China(Grant No.2016YFA0202702)
文摘Among all-solid-state batteries, rechargeable Al-ion batteries have attracted most attention because they involve threeelectron-redox reactions with high theoretic specific capacity. However, the solid Al-ion conductor electrolytes are less studied. Here, the microscopic path of Al3+-ion conduction of NASICON-type(Al0.2Zr0.8)20/19Nb(PO4)3oxide is identified by temperature-dependent neutron powder diffraction and aberration-corrected scanning transmission electron microscopy experiments.(Al0.2Zr0.8)20/19Nb(PO4)3shows a rhombohedral structure consisting of a framework of(Zr,Nb)O6octahedra sharing corners with(PO4) tetrahedra; the Al occupy trigonal antiprisms exhibiting extremely large displacement factors. This suggests a strong displacement of Al ions along the c axis of the unit cell as they diffuse across the structure by a vacancy mechanism. Negative thermal expansion behavior is also identified along a and b axes, due to folding of the framework as temperature increases.
