N‐Doped Carbon‐Stabilized CoSe/NiSe ₂ Heterojunction Toward High‐Performance Supercapacitors and Photorechargeable Power Systems

ABSTRACT Photorechargeable power systems (PPSs) based on supercapacitors (SCs) provide a sustainable solution for alleviating the energy crisis. However, sluggish kinetics in SCs are insufficient to meet the requirements of rapid photogenerated charge storage; achieving efficient self‐charging remains a challenge. Here, PPSs integrating flexible solid‐state asymmetric SCs (FSASs) with N‐doped carbon‐stabilized CoSe/NiSe 2 heterojunction (N‐C@CoSe/NiSe 2 ) and flexible solar cells (FSs) are precisely designed to achieve efficient self‐charging capacity. Theoretical calculations reveal that the robust built‐in electric field (BIEF) at the heterointerface accelerates electron reconstruction and enhances the affinity of OH − , thereby endowing abundant electroactive sites and fast reaction kinetics. The stable interfacial chemical bond between the N‐C frame and the CoSe/NiSe 2 heterojunction significantly strengthens the BIEF while buffering volume expansion during electrochemical, improving the integral structural stability. The N‐C@CoSe/NiSe 2 ingeniously combines synergistic optimization of reaction kinetics and structural stability, achieving high capacitance (2124 F g −1 ) and excellent cycling stability. The assembled FSASs deliver excellent energy storage capacity (70.8 Wh Kg −1 ). More importantly, integrated PPSs achieve a highly efficient photogenerated charge storage capacity of 4.5 V min −1 and sustainability, powering wearable electronic devices and small unmanned aircraft. This work provides scientific insights and guidance for designing robust heterogeneous and advancing the exploitation of next‐generation sustainable power systems.