<p>The accelerating adoption of electric transportation and portable electronics has intensified the pursuit of Li-ion batteries (LIBs) with high energy output and prolonged operational lifespans. However, the conventional graphite anode suffers from interfacial degradation and capacity fading, particularly under high-voltage operation and prolonged cycling. In this study, graphite anodes were surface-modified with Nb₂O₅, ZnO, and NiO to improve their structural integrity and electrochemical performance. The formation of crystalline metal-oxide layers on graphite was verified through X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. Among the modified samples, the C–NbO electrode exhibited superior reversible capacity of 361.4 mAh g⁻¹ for delithiation, excellent rate capability (200.7 mAh g⁻¹ at 2.0&#xa0;C), and remarkable cycling stability. Full-cell tests using LiNi_0.5Mn_1.5O₄ cathodes operating at high voltage demonstrated that Nb₂O₅ modification suppressed Mn²⁺ deposition and mitigated solid–electrolyte interphase layer growth, as confirmed by high-resolution transmission electron microscopy and Raman analysis. Electrochemical impedance spectroscopy indicated a reduction in charge-transfer resistance and improved Li⁺ transport kinetics. The enhanced performance supports the use of Nb₂O₅-modified graphite as a reliable anode material for LIBs designed to operate under harsh conditions.</p> Graphical Abstract <p></p>