Role of Double Interfaces in Inspiring Energy Storage in CC@Ni(OH)Cl@NiO Flexible Electrodes
Interfacial engineering is highly promising in research field of flexible energy storage devices. Massive efforts have confirmed the beneficial effects of controlled interfaces in enhancing energy storage. Despite the extensive studies on constructing multilevel interfaces in flexible electrode fabricating, deep understanding of the role of interfaces from the electrochemical perspective remains lacking, specifically the operational feasibility in extreme condition. Herein, we designed a carbon cloth (CC) based double-interface CC@Ni(OH)Cl@NiO by a solvothermal, chemical bath, and subsequent annealing method. We obtained both remarkable areal capacitance (8290 mF cm-2 at 30 mA cm-2) and excellent cycling stability (73.9% capacitance retention after 1000 cycles) approximately doubled as compared to the single-interface CC@Ni(OH)Cl. Correspondingly, ultrahigh current tolerance is endowed with stable charge-discharge capacitance of 3580 mF cm-2 at 120 mA cm-2. A flexible quasi-solid-state asymmetric supercapacitor device, CC@Ni(OH)Cl@NiO//graphene, has been assembled, which achieved favorable capacitive ability and splendid flexibility as well as mechanical stability. Through synchrotron radiation technique, we demonstrated that synergistic double interfaces afford the benefits of stable Ni-O covalency during electrochemical cycles, meanwhile bring about more structural distortion and active electronic behavior on the surface state, which simultaneously stimulated capacitive ability and stability. Importantly, our study reveals a positive role of double interfaces from electrochemical perspective of flexible electrodes for widespread energy storage in the future.