Mg2+ substitution effect on the electrochemical performance of LiNi0.8−xMgxCo0.1Mn0.1O2 (x = 0.0, 0.01, 0.02, 0.03, 0.04, 0.05) cathode materials for LIBs

To enhance the performance of cathode materials in lithium-ion batteries, novel compositions and synthesis methods are continually being explored. This study focuses on the substitution of Mg into LiNi0.8Co0.1Mn0.1O2 to develop LiNi0.8−xMgxCo0.1Mn0.1O2 (x = 0.0, 0.01, 0.02, 0.03, 0.04, and 0.05) cathode materials using the sol–gel auto-combustion approach. The materials synthesized at 850 °C/18 h are characterized by TG/DTA, XRD, FESEM with EDS, FT-IR, cyclic voltammetry, and galvanostatic charge/discharge studies. XRD confirmed the rhombohedral–hexagonal structure of the system with the space group R3̄m. Field emission scanning electron microscopy indicated a slight agglomeration morphology and size distribution from 200 to 320 nm. The initial discharge capacities are 214.84 and 233.57 mA h g−1, tested at a rate of 0.1 C in an operating voltage range of 3.0–4.6 V, and are found to be improved for the x = 0.03 material. Compared to the undoped sample, the Mg-doped LiNi0.77Mg0.03Co0.1Mn0.1O2 exhibited better retention capacity (96.48%) over five cycles. In addition, the cyclic voltammetry results demonstrated improved cycling stability and higher anodic current for the Mg-doped samples. Electrochemical impedance spectroscopy revealed that Mg substitution reduced the transfer resistance, enhancing the material’s conductivity and overall electrochemical performance.