Trace level doping of lithium-rich cathode materials

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 4; no. 9; pp. 3538 - 3545
• Main Authors: Lengyel, Miklos, Shen, Kuan-Yu, Lanigan, Deanna M, Martin, Jonathan M, Zhang, Xiaofeng, Axelbaum, Richard L
• Format: Journal Article
• Language: English
• Published: 01.01.2016
• Subjects: Cathodes; Dopants; Electric potential; Electric vehicles; Electronics; Energy density; Rechargeable batteries; Voltage
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta07764h

Lithium ion batteries have revolutionized portable electronics and have the potential to electrify the transportation sector. Lithium-rich cathode materials with the composition xLi sub(2)MnO sub(3).(1-x)Li(Ni sub(1/3)Mn sub(1/3)Co sub(1/3))O sub(2) have received considerable attention as candidates for Plug-in Hybrid Electric Vehicles (PHEVs) and Electric Vehicles (EVs). Cathodes made from these materials display high capacity (>200 mAhg super(-1)) and good cycling stability, offering twice the energy density of currently available intercalation materials. Unfortunately, their performance is plagued by voltage fade due to a layered-spinel phase transformation. Herein, using spray pyrolysis, we show that certain inexpensive trace level ( less than or equal to 1%) dopants can help in mitigating voltage fade, when the material is cycled between 2.0-4.6 V. The dopants lead to greater capacity loss than what would be expected from a capacity that is strictly based on a change in the transitional-metal oxidation state. The results imply that a portion of the capacity of these materials comes from reversible oxygen chemistry. These findings could put a different perspective on fade mechanism prevention.