Synthesis of Sn doped and rice husk derived activated carbon surface coating NMC 811 through solution combustion method

Nickel rich cathode material is widely used in lithium-ion batteries due to its high capacity, low cost, and environmentally friendly. However, high nickel content leads to capacity decay, poor rate capability, thermal and structural instability. To overcome these drawbacks, in this work, nickel rich NMC 811 was doped with tin to form LiNi_0.8Mn_0.1Co_0.1-xSn_xO₂ with x = 0.01, 0.03, 0.05 via solution combustion method. Crystal structure, morphology, particle size, surface area and electrochemical performance were characterized and analyzed. The optimum Sn-doped NMC 811 was further surface modified with rice husk derived activated carbon. Electrochemical characterization showed that dual modification with 3% Sn-doping and rice husk derived activated carbon coating (NMC-Sn/C) provided the highest conductivity of 1.73 × 10⁻⁴ S/cm, which was higher than that of NMC without modification (1.88 × 10⁻⁵ S/cm). The capacity reached 84.60 mAh/g with retention of 75% after 50 cycles. These improvements originate from the stabilizing effect of Sn-doping and rice husk derived activated carbon coating that reduces the direct contact between NMC 811 and electrolyte. Hence, modifications with Sn-doping and rice husk derived activated carbon coating are promising to enhance the electrochemical performance of NMC 811.