High-Energy Ni-Rich Li[NixCoyMn1-x-y]O2 Cathodes via Compositional Partitioning for Next-Generation Electric Vehicles

Chong S. Yoon, Kang Joon Park, Un Hyuck Kim, Ki H. Kang, Hoon Hee Ryu, Yang Kook Sun

Research output: Contribution to journalArticle

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Abstract

Electrochemical properties and structural and thermal stability of Li[Ni0.65Co0.13Mn0.22]O2 (FCG65), Li[Ni0.75Co0.08Mn0.17]O2 (TSFCG75), and Li[Ni0.85Co0.05Mn0.10]O2 (TSFCG85) with concentration gradients of Ni and Mn were evaluated to comprehensively demonstrate the effectiveness of compositional gradation for a wide range of Ni-rich Li[NixCoyMn1-x-y]O2 (NCM) cathodes. The discharge capacities of FCG65, TSFCG75, and TSFCG85 were 194.2, 206.8, and 222.2 mAh g-1, respectively with capacity retention of over 90% after 100 cycles. The high capacities and enhanced cycling stability relative to those of conventional Ni-rich NCM cathodes were attributed to the compositional partitioning, strong crystallographic texture, and unique particle morphology. In addition, the highly correlated particle orientation helped to reduce the anisotropic internal strain induced by Li removal/extraction from the Ni-rich NCM cathodes. The accelerated aging test (storing the delithiated cathodes in an electrolyte at elevated temperature) reconfirmed the superior stability of the TSFCG85 cathode compared to the commercial Li[Ni0.82Co0.14Al0.04]O2 cathode, which exhibited fast structural degradation. Thus, NCM cathodes with concentration gradients represent a viable solution that simultaneously addresses the specific energy density, cycling and chemical stability, and safety issues of Ni-enriched NCM cathodes for general electromobility.

Original languageEnglish
Pages (from-to)10436-10445
Number of pages10
JournalChemistry of Materials
Volume29
Issue number24
DOIs
StatePublished - 2017 Dec 26

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