Molybdate flux growth of idiomorphic Li(Ni sub(1/3)Co sub(1/3)Mn sub(1/3))O sub(2) single crystals and characterization of their capabilities as cathode materials for lithium-ion batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 4; no. 19; pp. 7289 - 7296
• Main Authors: Kimijima, T, Zettsu, N, Yubuta, K, Hirata, K, Kami, K, Teshima, K
• Format: Journal Article
• Language: English
• Published: 01.05.2016
• Subjects: Agglomeration; Crystals; Discharge; Electrodes; Flux; Lithium-ion batteries; Molybdates; Rechargeable batteries
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c6ta01593j

A Li sub(2)MoO sub(4) flux enabled size-tunable idiomorphic Li(Ni sub(1/3)Co sub(1/3)Mn sub(1/3))O sub(2) (NCM) crystal growth. The crystal size was controlled from 0.26 to 4.4 mu m simply by changing the experimental conditions (i.e., solute concentration and reaction temperature). The obtained crystals individually dispersed in both water and N-methylpyrrolidone without unexpected agglomeration; however, Li deficiency and a thin amorphous-like layer formed on the NCM crystal surface during flux removal with water. We found that post-heat-treatment with LiOH significantly improved the discharge capacity of NCM. Recovery of the surface quality of the NCM crystals was primarily responsible for the capacity improvement. The electrodes achieved a high capacity of 81 mA h g super(-1) under a high current density of 2000 mA g super(-1), while the electrodes prepared from commercially available NCM showed a maximum of 65 mA h g super(-1). The rate and cycle performance of the flux-grown NCM crystals was highly dependent on the crystal size. Smaller crystals showed excellent discharge capacities at high C rates, whereas larger crystals showed better cycle performances.