In-Plane Assembled Single-Crystalline T-Nb2O5 Nanorods Derived from Few-Layered Nb2CTx MXene Nanosheets for Advanced Li-Ion Capacitors

Lithium-ion capacitors (LICs) have attracted enormous interest thanks to their competitive power/energy densities and long-duration lifespan. However, the sluggish insertion kinetics of battery-type anodes seriously limits comprehensive performance of LICs. It is therefore imperative yet significant to develop advanced anodes with high-rate Li(+)intercalation. Herein, first the in-plane assembled single-crystalline orthorhombic Nb(2)O(5)nanorods (T-Nb(2)O(5)NRs) are designed and constructed via efficient hydrothermal and subsequent annealing treatment by employing few-layered Nb(2)CT(x)nanosheets as a niobium-based precursor. The inherent formation mechanism of single-crystalline T-Nb(2)O(5)NRs is tentatively proposed. When evaluated as anode material for LICs, the T-Nb(2)O(5)NRs are endowed with robust crystalline skeletons and high diffusion dynamics benefiting from their appealing structure merits, and they exhibit a high-rate capacity of approximate to 147 mAh g(-1)at 2.0 A g(-1). The lithium storage process of the resultant single-crystalline T-Nb(2)O(5)is unveiled as well with in situ X-ray diffraction analysis. Furthermore, the T-Nb2O5NR-based LICs display a large energy density of approximate to 35.6 Wh kg(-1)at 8 kW kg(-1), along with exceptional capacity retention of approximate to 95% over 4000 cycles at 0.5 A g(-1). More significantly, the devised synthetic methodology and in-depth insights here will stimulate extensive development of single-crystalline T-Nb(2)O(5)NRs for next-generation LICs and beyond.