Characteristics of NMC811 after Surface Modification Using Rice Husk Derived Silica Coating

High nickel content in nickel manganese cobalt (NMC811, LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) resulted in high capacity but low structural stability. Surface modification of NMC811 via silica (SiO 2 ) coating is known to counter this problem, leading to better electrochemical performance. In this work, silica was synthesized from rice husk through sol-gel method with alkaline extraction followed by acidification process. The resulting silica was coated onto commercially available NMC811 to modify its surface via solid-state reaction method. The characterization results showed that the silica coated NMC811 demonstrated a higher conductivity and lithium diffusion coefficient of 2.85 x 10 -5 S/cm and 2.52 x 10 -14 cm 2 /s, respectively, compared to that of bare NMC811 (8.17 x 10 -6 S/cm and 1.75 x 10 -15 cm 2 /s, respectively). This result confirms that the silica derived from rice husk can be used as a potential low-cost material to modify the surface and thus to increase the electrochemical performance of commercial NMC811.