Architectured Synthesis of a NMC core/shell cathode: Tailoring microstructure with tungsten oxide barrier for improved stability of Lithium- ion batteries

Abstract

High-Ni layered oxide cathodes (LiNixMnyCozO2, NMC) offer high energy density and cost efficiency for lithium-ion batteries but face challenges such as capacity loss, voltage decay, and structural instability due to Ni2+ migration and oxygen loss. To address these issues, a core/shell NMC design was developed, featuring a Ni-rich NMC90 core for high capacity and a Mn-rich NMC622 shell for enhanced stability. Additionally, a tungsten oxide (WO3) interlayer was introduced as a diffusion barrier to suppress interfacial degradation and elemental migration. The material was synthesized via a cost-effective, oxalate-assisted coprecipitation method with in-situ lithium incorporation. Characterization using SEM, EDX, XRD, and GCD confirmed the R3m phase formation and improved electrochemical performance. The WO3-modified core/shell cathode showed more than a twofold reduction in degradation rate, demonstrating a promising route toward stable, high-performance NMC cathodes for next-generation lithium-ion batteries.