Microstructure-optimized concentration-gradient NCM cathode for long-life Li-ion batteries. (January 2022)

• Record Type: Journal Article
• Authors: Park, Geon-Tae; Ryu, Hoon-Hee; Noh, Tae-Chong; Kang, Gyeong-Cheol; Sun, Yang-Kook
• Is Part Of: Materials today. Volume 52(2022)
• Page Start: 9
• Page End: 18
• Publication Date: 2022-01
• Subjects: LIBs Li-ion batteries -- EVs Electric vehicles -- NCA Li[NixCoyAl1-x-y]O2 -- NCM Li[NixCoyMn1-x-y]O2 -- CG Concentration gradient -- FCG Full concentration gradient -- FCG NCM78 Li[Ni0.78Co0.10Mn0.12]O2 -- FCG NCM78_790 oC FCG NCM78 calcined at 790 oC -- FCG NCM78_850 oC FCG NCM78 calcined at 850 oC -- TM Transition-metal -- SEI Solid electrolyte interphase; Ni-rich layered cathode -- Concentration gradient cathode -- Microstructural optimization -- Long-life battery; Materials science -- Periodicals; Metallurgy -- Periodicals; Metal-work -- Periodicals; Biomedical and Dental Materials -- Periodicals; Manufactured Materials -- Periodicals; Metals -- Periodicals; 620.11
• DOI: 10.1016/j.mattod.2021.11.018
• Languages: English
• ISSNs: 1369-7021

Abstract

Graphical abstract: Abstract: Herein, a comprehensive investigation of the effect of calcination temperature on the physicochemical properties of full-concentration-gradient Li[Ni0.78 Co0.10 Mn0.12 ]O2 (FCG NCM78) and the electrochemical performance of FCG NCM78 cathodes was conducted. The electrochemical performance of the FCG NCM78 cathode was significantly influenced by the physical properties of FCG NCM78, such as crystallinity, compositional gradient, and morphology. The crystallinity of FCG NCM78 increased with increasing calcination temperature; however, the compositional gradient and radial alignment of rod-shaped primary particles increasingly disappeared at calcination temperatures exceeding the optimal calcination temperature. FCG NCM78 calcined at the optimal calcination temperature retained the morphological texture of its precursor and demonstrated high crystallinity; the resulting cathode exhibited remarkable cycling stability, thereby retaining 86.3% of its initial capacity after 4000 cycles, and superior rate capability due to the availability of nearly straight diffusion paths for Li-ion transport across adjacent primary particles. In contrast, excessively coarsened FCG NCM78 cathode particles, which are obtained at high calcination temperatures, develop permanent microcracks during cycling, thereby facilitating severe structural damage of the cathode material by parasitic surface reactions and the rapid deterioration of the solid electrolyte interphase layer on the graphite anode surface due to the crossover of dissolved transition-metal ions. Therefore, for superior electrochemical performance, the physicochemical properties of FCG cathode materials should be carefully optimized by controlling the calcination process.