Synergistic effect of Al–B co-doping to boost the LiNi0.9Co0.05Mn0.05O2 properties in lithium-ion batteries

The high nickel and low cobalt cathode material, LiNixCoyMn1-x-yO2 (x>80%, y<10%), has become one of the preferred materials in next-generation new energy vehicles due to its high energy density, but its wide use in the market is limited because of poor structural stability triggered by the high nickel content. In this work, the 0.002 mol of Al3+ and 0.001 mol of B3+ co-doping LiNi0.9Co0.05Mn0.05O2 cathode materials (0.2Al-0.1B-LNCM90) were successfully synthesized by simple solid-phase sintering, which were confirmed by ICP, EDS and XPS. The results showed that the modified samples integrate the effect of Al-doping and B-doping. On the one hand, B occupied the tetrahedral gap of the oxygen array in the transition metals (TM) and lithium layers, which increases the lattice parameter c. On the other hand, the strong Al–O bond reduced the evolution of lattice O. The cell assembled with the 0.2Al-0.1B-LNCM90 transferred an initial discharge capacity of 227 mAh g−1 at 0.1 C between 2.75 and 4.3 V, with a discharge capacity of 176 mAh g−1 after 100 cycles, which is higher than that of 101 mAh g−1 for the pristine material. Moreover, it also delivered a superior discharge specific capacity of 169 mAh g−1 at 5 C, compared to 128 mAh g−1 for the pristine material.