Accurate estimation of Li/Ni mixing degree of lithium nickel oxide cathode materials

• Published in: Chinese physics B Vol. 33; no. 5; pp. 58202 - 58206
• Main Authors: Chen, Penghao, Xu, Lei, Yu, Xiqian, Li, Hong
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and IOP Publishing Ltd 01.05.2024
• Subjects: discharge capacity; high-nickel ternary cathode; Li/Ni mixing; lithium nickel oxide; spherical harmonics function
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/ad3036

Li/Ni mixing negatively influences the discharge capacity of lithium nickel oxide and high-nickel ternary cathode materials. However, accurately measuring the Li/Ni mixing degree is difficult due to the preferred orientation of lab-based XRD measurements using Bragg–Brentano geometry. Here, we find that employing spherical harmonics in Rietveld refinement to eliminate the preferred orientation can significantly decrease the measurement error of the Li/Ni mixing ratio. The Li/Ni mixing ratio obtained from Rietveld refinement with spherical harmonics shows a strong correlation with discharge capacity, which means the electrochemical capacity of lithium nickel oxide and high-nickel ternary cathode can be estimated by the Li/Ni mixing degree. Our findings provide a simple and accurate method to estimate the Li/Ni mixing degree, which is valuable to the structural analysis and screening of the synthesis conditions of lithium nickel oxide and high-nickel ternary cathode materials.