Heterostructure creation has been an effective strategy to synthesise hybrid supercapacitor electrodes by combining materials of various charge storage mechanisms, leveraging the advantages, and minimising the drawbacks of individual materials as separate entities. Herein, a hybrid supercapacitor electrode has been fabricated producing ternary NiSe2/rGO/PANI heterostructure, through simple hydrothermal followed by in-situ polymerisation techniques. Owing to the synergy between the materials, the electrode decorated on a flexible carbonaceous template exhibits a remarkable capacity of 657.36C g−1@1 A g−1 offering excellent stability over 12,000 cycles. Subsequently, a hybrid asymmetric supercapacitor (HASC) constructed using NiSe2/rGO/PANI as a positive electrode and AC as a negative electrode possesses a high energy density of 98.82 Wh kg−1 at a power density of 750.05 W kg−1 with a capacitive retention of 95.04 %. Encasing the complete device with Polydimethylsiloxane (PDMS) mould acting as an energy storage band demonstrates an unaltered device performance at various bending angles of 0° to 135°, which refers to its compatibility in flexible electronics. Further, the practical usefulness of the as-designed prototype has been exhibited by powering several devices such as; Light Emitting Diodes (LEDs) of various colours, homemade windmill, Arduino board, and LCD monitor via charging through a commercial silicon solar panel paving the way to bloom renewable energy conversion and storage.