Li(Ni_xMn_yCo_z)O₂ with high specific surface area prepared by electrospinning

ABSTRACT

Reaction polarization of the Li(Ni_xMn_yCo_z)O₂ (NMC) cathode materials can be significantly alleviated by depolarization and pre-lithiation, which respectively produce electrolyte protective layer and double-layer lithium structure. These structures can not only prevent Ni ions from dissolution but also increase the discharge capacity. However, as the size of the regular NMC particles is relatively large, the effect of depolarization and pre-lithiation is not significant. This work tries to prepare NMC with nanoscale structure and high specific surface area by electrospinning, and studies the effect on NMC morphology caused by calcination atmosphere, oxidation temperature, decarburization temperature and calcination temperature. It is hoped that the polarization can be further eliminated by optimizing the size, and the proportion of double-layer lithium formed in the pre-lithiation can be increased. The results reveal that after several steps including pre-oxidation at 200°C, decarburization at 550°C and calcination at 750°C, nano lamellar structures with size of about 1–3 μm and thickness of about 30 nm can be produced under O₂ flow of 200 SCCM. NMC with nano lamellar structures will further alleviate the polarization and produce a higher proportion of double-layer lithium structure by pre-lithiation, resulting in a significant improvement of the discharge capacity.

KEYWORDS:

• Li(Ni_xMn_yCo_z)O₂ cathode material
• specific surface area
• electrospinning
• nano lamellar structure

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Shenzhen Science and Technology Research Grants [No. JCYJ20150828093127698, No. JCYJ20170306165240649]; Postdoctoral Innovative Talent Support Program [No. BX20190001]; and Guangdong Science and Technology Research Grants [No. 2015B090927003].