<p>Sodium-ion hybrid capacitors (SICs) offer inherent energy-power synergy but are constrained by mismatched kinetics and life spans between the anode and cathode materials. Two-dimensional MoS₂@C composites demonstrate excellent kinetics and structural stability, thanks to the built-in electric field of the carbon heterostructure and its adaptability to volume changes. Yet, the carbon shell imposes a physical barrier to interfacial Na⁺ diffusion, while deep discharge induces the formation of crystalline Na₂S, accompanied by severe volumetric expansion and sluggish reversibility—factors that accelerate capacity fading and structural degradation. To address these challenges, a trace-level Ni doping strategy is introduced, enabling precise modulation of the composite’s interlayer structure, electronic configuration, and reaction pathway. Ni incorporation expands the MoS₂ inter-layer spacing, reconstructs short-range ordered nanocrystals within a hierarchically porous network, and promotes Na⁺ diffusion by weakening interlayer van der Waals forces. Orbital hybridization between Ni-3d and Mo-4d/S-3p states enhances electronic conductivity and reduces charge transfer resistance. Critically, Ni doping enhances electron transfer from Ni to sulfur, which weakens Na–S bonds and promotes the formation of amorphous Na₂S, thereby suppressing crystalline Na₂S and enabling a reversible MoS₂/Na₂S conversion mechanism for improved structural stability and cycling performance. As a result, the optimized MoS₂-Ni@C anode delivers a high reversible capacity of 334 mAh g⁻¹ at 10 A g⁻¹ with 68% retention after 10,000 cycles. When assembled into a SIC device (MoS₂-Ni@C//AC), it achieves an energy density of 135 Wh kg⁻¹ at a power density of 60.8 kW kg⁻¹ (based on anode mass), with 76% retention over 3,000 cycles.</p>