Nickel-rich layered LiNi0.8Mn0.1Co0.1O2 with dual gradients on both primary and secondary particles in lithium-ion batteries

Abstract

The Li + /Ni 2+ mixing in LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) leads to fast battery capacity decay. Here we report a dual-gradient nickel-rich layered cathode material (D-NMC811), using nickel-based metal organic framework of Ni-MOF-74. The formation of a protective layer with rock salt phase due to the reduced nickel oxidation state on the surface of the primary particles resists internal strain and suppresses further phase transition, thus alleviating crack generation. After 300 cycles at ⅓ C, a high half-cell capacity retention of 88.50% with 0.038% decay per cycle is observed. The full-cell battery displays a high capacity retention of >86.7% with a Coulombic efficiency of >99.86% at ⅓ C after 300 cycles. The 300 mAh pouch cell delivers an energy density of 216.4 Wh/kg. After 500 cycles at 1.0 C, it still displays 84.1% capacity retention while the battery with conventional NMC811 only shows a retention of 53.0% after 400 cycles. • Nickel-rich layered NMC material formed with MOF • Dual element concentration gradient on both primary and secondary particles • Enhanced structure stability through thin rock salt layer on surface • Improved battery capacity retention and cyclability Shang et al. report a nickel-rich cathode material with dual concentration gradients on both primary and secondary particles. The improved structure reliability of D-NMC811 during long cycling makes it promising for applications in high energy-density lithium ion batteries.