Tuning SEI chemistry and mesoporous carbon architecture in Nb₂O₅ nanocomposites for next-generation Lithium-Ion batteries

Carbon-based nanocomposites are key to advancing lithium-ion batteries due to their tunable conductivity and interfacial stability. In this work, Nb₂O₅/carbon nanocomposites were engineered with a carbon quantum dot (CQD)-derived matrix to regulate solid electrolyte interphase (SEI) chemistry and optimize mesoporous architecture. Multiphysics simulations show that the carbon framework suppresses uncontrolled SEI growth, reducing interfacial resistance and stabilizing capacity retention. Optimized mesopores (∼10 nm, porosity 0.5) enhance lithium-ion transport by increasing the effective diffusion coefficient by 35.4 %, yielding ∼15 mAh g⁻¹ higher capacity compared with non-optimized designs. The synergy between SEI regulation and mesoporosity enables high-rate capability and prolonged cycle life, outperforming pristine Nb₂O₅. These findings highlight the pivotal role of carbon integration in balancing interfacial chemistry and ion transport, providing a scalable design strategy for advanced Nb₂O₅/carbon anodes. Overall, this study establishes a framework for carbon-engineered electrode architectures that accelerate the development of high-performance, durable, and sustainable energy storage systems.