The ultralong Mo4O11 nanoribbons: Ultrasonic synthesis and topotactic transformation toward high-performance sodium-ion batteries

The design and synthesis of two-dimensional layered transitional metal oxides (TMOs) have been of great interest for their potential application in sodium-ion batteries (SIBs), due to the advantages such as multivalent ions and tunable interlayer spacing. However, achieving a well-defined crystal structural topology and geometric morphology in TMOs still remains a significant challenge, particularly in tailoring their polyhedral structures. Herein, the ultralong Mo 4 O 11 nanoribbons (Mo 4 O 11 -NR) were prepared by a simple aniline-assisted sonochemical method for the first time. The resulting nanoribbons possess a unique tunnel structure and exhibit topologically frustrated arrangements of MoO 6 octahedra and MoO 4 tetrahedra. When used as anodes for SIBs, multielectron redox reactions of Mo 4 O 11 -NR allow for high-capacity energy storage. The buffered volume expansion of the nanoribbons accommodates the strain that occurs during cycling, thereby boosting cycling stability. The topologically frustrated arrangements of the polyhedra further contribute to the efficient storage and transfer of ions and electrons. As a result, Mo 4 O 11 -NR anode achieves a reversible specific capacity of 101 mA h g −1 after 2,000 cycles, when subjected to a high current density of 5 A g −1 . This exceptional performance highlights the potential of Mo 4 O 11 -NR material as an advanced anode material for high-power devices.