Improving electrochemical performance of NMC811 battery cathode with Indonesian rice husk-derived silica surface coating

• Rice husk can be utilized as a cheap and renewable silica source. • NMC811 can be surface modified with rice husk silica through solid state method. • Surface modification of NMC811 with rice husk silica result in an improved electrochemical performance. Nickel-rich nickel manganese cobalt (LiNi x Mn y Co z O 2 x ≥ 0.8) cathode material is widely studied due to its high specific capacity, high energy density, and low toxicity. Despite these advantages, NMC811 (LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) suffers from structural instability and is susceptible to degradation upon exposure to ambient air. Surface coating using silica has been demonstrated to mitigate these issues by acting as a protective barrier against air and electrolyte. In the present study, rice husk was used as a cost-effective and renewable source of silica for coating NMC811. The extracted silica was characterized by an amorphous structure, spherical particles, and a purity of 97.54%. Coating with 1.5 wt.% rice husk-derived silica improved electrochemical performance of NMC811, yielding enhancements in electrical conductivity (3.11 × 10 -5 S/cm), lithium-ion diffusion coefficient (9.77 × 10 -14 cm 2 /s), and specific capacity (325.30 mAh/g) in comparison to pristine NMC811 (2.68 × 10 -5 S/cm, 3.63 × 10 -14 cm 2 /s, 212.93 mAh/g, respectively). These findings highlight the potential of rice husk-derived silica as sustainable and effective coating material for enhancing the stability and electrochemical performance of NMC811 cathodes.