MXene‐Assisted Bi ₂ MoO ₆ Heterogeneous Structures: Constructing Oxygen Vacancy for Accelerated Energy Storage Devices

ABSTRACT Two‐dimensional MXene‐based materials have recently attracted attention in supercapacitors and lithium ion batteries due to their excellent electrochemical performance. However, the capacity and agglomerate limits the development of MXene‐based materials. Herein, we constructed an oxygen vacancies‐enriched Bi 2 MoO 6 /MXene (Ov‐MBM) composite by utilizing NaBH 4 as an oxygen scavenging agent, through a simple electrostatic assembly of positively charged Ov‐Bi 2 MoO 6 (Ov‐BM) onto negatively charged MXene. MXene acts as a flexible interlayer to relieve the volume expansion of Bi 2 MoO 6 (BM) during the electrochemical process. It forms a conductive network that facilitates charge transfer. Subsequently, the Ov‐MBM composite exhibits a high volumetric capacity of 971 mAh cm −3 and excellent capacity retention of 88.6%. The fabricated asymmetric device demonstrates a maximum volumetric energy density of 179 Wh L −1 and retains 89.9% of its initial capacity after 10,000 cycles at 20 A g −1 . Moreover, the Ov‐MBM composite exhibits with a reversible capacity of 1801 mAh cm −3 at 0.1 A g −1 in Li‐ion storage and maintains a capacity of 817 mAh cm −3 at 5 A g −1 . This research work not only provides a high volumetric‐capacity bifunctional energy storage device but also highlights an effective synthetic strategy for interfacial interactions.