Optimization of conductive cyclized polyacrylonitrile content to enhance the structural stability of single-crystal LiNi0.8Co0.1Mn0.1O2 cathode materials for lithium-ion batteries

To optimize the electrochemical properties of Ni-rich cathode materials, CPAN@SC-NCM811 is prepared via surface modification of single-crystalline LiNi_0.8Co_0.1Mn_0.1O₂ cathode material by adding 1, 2 and 3 wt.% of polyacrylonitrile, respectively. Significantly, the results obtained from X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) verify the successful synthesis of CPAN@SC-NCM811 cathode, which exhibits better electrochemical properties compared to SC-NMC811. After thorough milling and calcination of 2 wt.% polyacrylonitrile with SC-NCM811, the initial discharge specific capacity of prepared S2 sample is 197.7 mAh g⁻¹ and the capacity retention reached 89.2% after 100 cycles at a rate of 1.0 C. Furthermore, the S2 sample exhibits superior rate performance compared to the other three samples, in which these superior electrochemical properties are largely attributed to the optimal ratio of conductive cyclized polyacrylonitrile coatings. Overall, this work offers guidelines for modifying the surface of SC-NCM811 cathode materials for lithium-ion batteries with exceptional cycling and rate performance.

Graphical abstract

Preparation schematic of the CPAN@SC-NCM811 cathode materials and the corresponding cycling performance of the assembled coin cells