Rational design of dual-ion doped cobalt-free Li-rich cathode materials for enhanced cycle stability of lithium-ion pouch cell batteries†

Abstract

The synergistic effect of single-crystal structure and dual doping in Li-rich cobalt-free cathode materials was thoroughly investigated. Lithium-ion pouch cells employing Sb/Sn doped Li_1.2Mn_0.6Ni_0.2O₂ and graphite exhibited a specific capacity of 191.01 mA h g⁻¹ at 1C rate and exceptionally stable performance upon cycling, with capacity retention of 87.24% of their initial capacity after 250 cycles at 1C rate. The strategic combination of morphology manipulation and dual ion doping has markedly diminished cation mixing and expanded the Li interstitial sites within the cathode lattice. This work offers significant insights into the mechanisms responsible for the structural decline of Li-rich cobalt-free cathodes, emphasizing the importance of stabilizing the cathode lattice structure at high potential. These findings suggest promising potential for this material to meet the demanding energy density criteria for electric vehicles. Finally, this research provides practical strategies for effectively implementing high-voltage cobalt-free cathodes, offering valuable guidance for future applications.