Structural Optimization of Al-Doped Li[Ni0.90Co0.05Mn0.05]O2 Cathode for Li-Ion Batteries. Issue 11 (1st November 2022)

• Record Type: Journal Article
• Authors: Sun, H. Hohyun; Pastel, Glenn R.; Zhang, Sheng S.; Tran, Dat T.; Allen, Jan L.
• Is Part Of: Journal of the Electrochemical Society. Volume 169:Issue 11(2022)
• Publication Date: 2022-11-01
• Subjects: Batteries Li-ion -- XRD -- Ni-rich -- Layered cathode -- Al-dopant; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/1945-7111/aca223
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Aluminum is a well-known dopant element as it is used in Li[Ni0.80 Co0.15 Al0.05 ]O2 but its optimized usage in Li[Ni x Co y Mn z ]O2 cathodes with x ≥ 0.90 has not been explored in depth. Here, we survey various Al-dopant concentrations (0.5, 1, 2, 3, and 5 mol%) to investigate the effect of Al-doping of highly Ni-rich layered Li[Ni0.90 Co0.05 Mn0.05 ]O2 cathode with respect to the electrochemical and structural properties. It is shown that Al is effective in enhancing the electrochemical performance of the Li[Ni0.90 Co0.05 Mn0.05 ]O2 cathode at higher than 1 mol% concentrations but becomes detrimental at 3 mol% or greater concentrations. In particular, Li[Ni0.90 Co0.05 Mn0.05 ]O2 with 2 mol% Al-doping delivers the most optimal electrochemical performance with 93% capacity retention over 100 cycles at 0.5 C within the 2.7–4.3 V voltage range as compared to the 85% retention of Li[Ni0.90 Co0.05 Mn0.05 ]O2 under the same conditions vs Li 0 /Li + in half cells. Analyses of the ex situ and in situ X-ray diffraction patterns, cell impedances over 100 cycles, and cross-sectional electrode images reveal that appropriate amounts of Al in the layered structure alleviate the extent of unit cell volume changes during charge, but excessive Al-dopant addition leads to the formation of γ -LiAlO2 byproducts that consume available Li to significantly impair the efficacy of the cathode.