In this study, nanostructured nickel sulfides (NiS, Ni₃S₂ and NiS/Ni₃S₂) were fabricated directly on the surface of flexible carbon fiber cloths by simply modifying the deposition parameters of pulse-reversal (PR) electrodeposition method and utilized as binder-free flexible electrodes for aqueous hybrid supercapacitors (SCs). X-ray photoelectron spectroscopy and contact angle measurement studies verifies that the surface of heterostructure NiS/Ni₃S₂ electrode has enriched Ni³⁺ sites and highly hydrophilic nature. Consequently, the heterostructure NiS/Ni₃S₂ electrode demonstrated superior rate capability than that of both single phase NiS and Ni₃S₂ electrodes. Additionally, the hybrid SC device based on the flexible NiS/Ni₃S₂ electrode delivered a capacity of 40.4 mAh g⁻¹ at a current density of 2 A g⁻¹ and representing a maximum energy density of 32.3 Wh kg⁻¹ at an impressive power density of 1.6 kW kg⁻¹. Furthermore, the device provided excellent electrochemical stability with a capacity retention of 86.2%, even after a 120-h floating test. Hence, the heterostructure NiS/Ni₃S₂ with interlaced nanosheets morphology should be considered as promising binder-free flexible electrode materials for next-generation energy storage applications.