MoNb12O33 as a new anode material for high-capacity, safe, rapid and durable Li+ storage: structural characteristics, electrochemical properties and working mechanisms†
Intercalation-type niobium-based oxides are considered as promising anode materials for lithium-ion batteries owing to their high theoretical/practical capacities, long-term cyclability, and high safety. However, studies in this research field are still very limited. Here, we explore MoNb12O33 as the first molybdenum niobium oxide anode material, and prepare microsized MoNb12O33 particles (M-MoNb12O33) and porous MoNb12O33 microspheres (P-MoNb12O33) based on solid-state reaction and solvothermal methods, respectively. MoNb12O33 shows a Wadsley–Roth crystal structure, consisting of 3 × 4 × ∞ NbO6 octahedra linked by corner-sharing MoO4 tetrahedra. This very open and stable structure results in fast Li+ diffusivity and superior structural stability, respectively. These structural merits together with the nanosizing effects in P-MoNb12O33 lead to outstanding electrochemical properties in its half cell, including a high practical capacity (321 mA h g−1 at 0.1C), significant intercalation pseudocapacitive contribution (85.5% at 1.1 mV s−1), prominent rate capability (200 mA h g−1 at 10C), and superior cyclability (capacity retention of 95.7% after 1000 cycles at 10C). Moreover, outstanding electrochemical properties of a LiMn2O4//P-MoNb12O33 full cell are also achieved, such as a high reversible capacity (274 mA h g−1 at 0.1C), good rate capability (106 mA h g−1 at 10C), and superior cyclability (capacity retention of 93.9% after 1000 cycles at 5C). All these findings indicate that P-MoNb12O33 can be a practical anode material for high-capacity, safe, rapid and durable Li+ storage.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry A Most Popular Articles