Performance improvement of Ni-rich layered cathode by doping

Abstract

The 1 mol% of Nb dopant elongates primary particles and align them in the radial direction, creating a composition that dissipates the abrupt internal strain caused by H2-H3 phase transition near the end of charging. Nb doping of Li[Ni0.855Co0.13Al0.015]O2 changes its primary particle morphology to allow precise ordering of its microstructure. The negation of the internal strain generally improves the long term cycling stability that is achieved by Nb-doped Li[Ni0.855Co0.13tjAl0.015]O2 cathode(Nb-doped cathodes retain 90 % of its initial capacity after 1000 cycles while undoped cathodes retains 57.3%). The Nb-doped cathode also stands out for enhanced chemical and structural stability during calendar aging and under thermal stress. Simple strategy of putting Nb ions in cathode during the lithiation of Li[Ni0.855Co0.13Al0.015]O2, proposed in this paper, represents an effective solution guaranteeing sufficient battery life, safety, and fast charging without compromising battery capacity for next-generation electric vehicles. Moreover, the enhanced chemical and mechanical stability of the Nb-doped NCA85 cathode can used at fast charging condition; thus, the Nb-doped NCA85 cathode has stable cycling for 500 cycling even when charged at 3 C (full charge takes 20 minutes).