Improved preparation efficiency and electrochemical performance of LiNi0.8Co0.15Al0.05O2 cathode material by oxalic acid and freeze-drying

LiNi0.8Co0.15Al0.05O2 has attracted attention due to its high capacity and low cost. Herein, we report a method for the rapid and efficient preparation of NCA cathode materials using oxalic acid with freeze-drying techniques, and compare the differences of electrochemical properties for different metal concentrations. The solvent volatilization by liquid nitrogen freezing and freeze-drying techniques resulted in a more uniform mixing of metal ions while reducing the reaction time and energy consumption. The results characterized using X-ray diffraction revealed that the layered structure of the material was better and the cation mixing was lower when the metal ion concentration in the solution reached 0.15 mol L−1. The electrochemical data revealed an initial charge–discharge capacity of 195 mAh g−1 at 0.1 C, capacity retention of 88.75% for 100 cycles at 1 C, and a discharge capacity of 139.7 mAh g−1 at 5 C. In addition, the cyclic voltammetry and electrochemical impedance spectroscopy reflect the material has low electrode polarization and excellent lithium-ion diffusion coefficient. The initial material diffusion coefficient is $$2.673 \times 10^{-15}\text{ cm}^{2} \mathrm{S}^{-1}$$ ; after 50 and 100 cycles, it is $$6.040 \times 10^{-16} \text{cm}^{2}\mathrm{S}^{-1}$$ 10−16 cm2S−1 and $$1.704 \times 10^{-16} \text{cm}^{2}\mathrm{S}^{-1}$$ respectively. The results provide a new idea for the energy-efficient synthesis of LiNi0.8Co0.15Al0.05O2.