Boron-Mediated Reconfiguration of Charge Dynamics and Structural Integrity in P2-Type Layered Metal Oxide Cathodes

Abstract

The rational tuning of layered metal oxide cathodes is central to advancing sodium-ion battery performance, particularly under high-voltage operation. Herein, the role of light weight boron as a covalent dopant is investigated to modulate the charge dynamics and structural robustness of P2-type Na_0.67Ni_0.33Mn_0.67O₂ cathodes. Through strategic boron (B) doping at the oxygen framework, a reconfiguration of local bonding environments is observed, which mitigates transition-metal migration and stabilizes the layered lattice during high-voltage cycling. Electrochemical analyses reveal a trade-off between enhanced voltage retention and marginal capacity suppression at elevated doping levels, attributed to altered Na⁺ diffusion pathways and phase evolution dynamics. Complementary structural and spectroscopic studies indicate suppressed phase transitions due to anionic redox, underscoring the dual role of boron in reinforcing both electronic transport and structural resilience. This work delineates the nuanced impact of B-doping on layered oxide chemistry, offering insight into defect-driven performance engineering for next-generation Na-ion energy storage systems.