Interfacial engineering is highly promising in the 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 the fabrication of flexible electrodes, a deep understanding of the role of interfaces from the electrochemical perspective is lacking, particularly the operational feasibility in extreme conditions. 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 double than those for the single-interface CC@Ni(OH)Cl. Correspondingly, ultrahigh current tolerance was endowed with a 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, was assembled, which achieved favorable capacitive ability and splendid flexibility as well as mechanical stability. Through the synchrotron radiation technique, we demonstrated that synergistic double interfaces afford the benefits of stable Ni–O covalency during the electrochemical cycles, and 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 the electrochemical perspective of flexible electrodes for widespread energy storage in the future.

中文翻译：

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双界面在激发CC @ Ni（OH）Cl @ NiO柔性电极中的储能装置中的作用†

在柔性储能装置的研究领域中，界面工程是非常有前途的。大量的努力已经证实了受控界面在增强能量存储方面的有益作用。尽管对在柔性电极的制造中构造多级界面进行了广泛的研究，但是从电化学的角度缺乏对界面作用的深入了解，特别是在极端条件下的操作可行性。本文中，我们通过溶剂热，化学浴和随后的退火方法设计了一种基于碳布（CC）的双界面CC @ Ni（OH）Cl @ NiO。我们获得既显着的面积电容（8290μF的厘米^-2在30mA厘米^-2）和出色的循环稳定性（1000次循环后的73.9％的电容保持率），大约是单界面CC @ Ni（OH）Cl的两倍。相应地，在120 mA cm ^{-2的情况下}，超高电流耐受性具有3580 mF cm ^-2的稳定充放电电容。组装了柔性准固态非对称超级电容器CC @ Ni（OH）Cl @ NiO //石墨烯，获得了良好的电容性能和出色的柔韧性以及机械稳定性。通过同步辐射技术，我们证明了协同双界面在电化学循环过程中具有稳定的Ni-O共价优势，同时带来了更多的结构畸变和表面态的主动电子行为，同时激发了电容性和稳定性。重要的是，我们的研究从柔性电极的电化学角度揭示了双界面在未来广泛存储能量中的积极作用。