Li3PO4 with the structure orthorhombic phase P m n 21 (31) is a promising solid electrolyte for all solid state battery.
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In contrast to X-Ray, the neutron Fourier map shows that Li atom is visible to neutron due to a negative scattering length of Li (−1.90).
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The elongation direction of the Lithium diffusion pathway was determined from low temperature neutron data.
Abstract
The solid electrolyte, Li3PO4 has been prepared by a wet chemical reaction. The crystal structure of Li3PO4 was measured at room temperature by a high resolution powder diffraction (HRPD) at the Neutron Scattering Laboratory, National Nuclear Energy Agency (BATAN), Indonesia. Another series of neutron data at 3 K and 300 K were measured by an ECHIDNA at Australian Center for Neutron Scattering, ANSTO, Australia. Based on how neutron and X-rays interact with matter, it is also important to perform the x-ray diffraction on Li3PO4. The purpose is to understand the insight crystal structure of Li3PO4 from two different methods. Both refinement results showed that crystal structure belong to the β-Li3PO4 with orthorhombic phase P m n 21 (31), with the lattice parameters are a = 6.1168 Å, b = 5.2498 Å, c = 4.8723 Å. Fourier method employed to reveal the main difference between neutron and X-rays sources. It is clearly shown that Li atom is visible to neutron. The negative scattering length of Li (−1.90) gave a negative intensity in the neutron Fourier map. In contrast to neutron, X-Ray interacts with electron gave a positive intensity but the heavy atom P dominates the intensity due to its high number of electron. The neutron can provide more detail in the structure information. By comparing the 300 K data with data 3 K, the Li-ions diffusion can be observed from the neutron Fourier maps, and the Li-ions elongation pathway can be seen from the 3-D structure model. It can be concluded here that neutron is an indispensable tool to observe the lithium ion battery materials.
