MoSe2/Bi2Se3 Heterostructure Immobilized in N‐Doped Carbon Nanosheets Assembled Flower‐Like Microspheres for High‐Rate Sodium Storage

Abstract A key challenge for sodium‐ion batteries (SIBs) lies in identifying suitable host materials capable of accommodating large Na + ions while addressing sluggish chemical kinetics. The unique interfacial effects of heterogeneous structures have emerged as a critical factor in accelerating charge transfer and enhancing reaction kinetics. Herein, MoSe 2 /Bi 2 Se 3 composites integrated with N‐doped carbon nanosheets are synthesized, which spontaneously self‐assemble into flower‐like microspheres (MoSe 2 /Bi 2 Se 3 @N‐C). Electrochemical measurements and density functional theory (DFT) calculations underscore the significant improvement in reaction kinetics enabled by the interfacial effects and structural advantages of the MoSe 2 /Bi 2 Se 3 composite. Remarkably, the flower‐like nanosheet morphology provides more storage sites, while the uniformly distributed heterostructure can optimize carrier concentration and alter electric field distribution, thereby facilitating charge transfer and enabling additional sodium ion storage. When employed as an anode material for SIBs, MoSe 2 /Bi 2 Se 3 @N‐C exhibits exceptional performance, delivering a reversible capacity of 521.4 mAh g −1 at 1 A g −1 for 800 cycles and 407.9 mAh g −1 at 10 A g −1 over 1400 cycles. Notably, the capacity can be fully restored to its initial level after cycling at high current densities. This study, combining experimental and theoretical insights, provides a novel perspective on interface engineering to advance the practical application of SIBs.