Site‐Selectively Engineered MoS 2 /ReS 2 Heterostructures for High‐Performance Supercapacitors

Layered MoS 2 holds great potential for supercapacitors; however, its intrinsically low electrical conductivity, sluggish electrochemical kinetics, and susceptibility to Mo dissolution severely hamper its electrochemical performance. Here, we propose a selective‐doping‐coupled heterostructure engineering strategy, in which atomic Fe preferentially incorporates into the MoS 2 domain, while the local structure of the ReS 2 component remains largely preserved, forming an Fe‐doped MoS 2 /ReS 2 (Fe‐MRS) heterostructure. Theoretical and experimental results reveal the formation of a built‐in electric field at the Fe‐MRS interface, driving electron transfer from ReS 2 to Fe‐doped MoS 2 , reconfiguring the Mo‐S electronic structure, while simultaneously strengthening Mo─S bonds and suppressing Mo dissolution. Moreover, Fe incorporation is energetically favored at octahedrally coordinated Mo sites within the MoS 2 domain, modulating the local electronic environment of the MoS 2 domain and thereby facilitating coupled electron/ion transport. Consequently, the Fe‐MRS electrode delivers high specific capacitance and excellent cycling stability with a capacitance retention of 97.0% over 5000 cycles. Moreover, asymmetric supercapacitors assembled with the Fe‐MRS anode achieve a high energy density of 55.2 Wh kg −1 at 1000 W kg −1 , maintaining good structural and mechanical robustness. This work offers clear guidance for leveraging selective doping to engineer heterostructures with enhanced electron‐ion coupling for advanced electrochemical energy storage systems.