Mixed-Phase Niobium Oxide as a Durable and Ultra-Fast Charging Anode for High-Power Lithium-Ion Batteries

The development of low-cost, high-power lithium-ion batteries requires durable anode materials that can store and release lithium quickly. Here a mixed phase of H-Nb₂O₅ and M-Nb₂O₅ (denoted as d-H,M-Nb₂O₅) that demonstrates excellent performance as an anode material for lithium storage is reported. Experimental and computational analyses reveal several salient features of d-H,M-Nb₂O₅. First, the edge-sharing arrangement between the mixed niobium oxygen polyhedral block structures helps alleviate volume expansion during cycling, thereby enhancing stability and reversibility. Second, the mixed-phase structure facilitates a continuous pathway for lithium ion adsorption These characteristics allow for sequential transport of lithium ions, enabling fast charging. As a result, the d-H,M-Nb₂O₅ electrode material exhibits a high capacity of 142 mAh g⁻¹ at an ultra-fast charging rate of 100 C, while maintaining 85% of its initial capacity after 5000 cycles. Moreover, its practical feasibility is established by demonstrating full-cell performance at a 5 C discharge/charge rate (13 mA cm⁻²), maintaining 79% of its capacity over 1000 cycles.