It remains a great challenge to design and manufacture battery‐type supercapacitors with satisfactory flexibility, appropriate mechanical property, and high energy density under high power density. Herein, a concept of porous engineering is proposed to simply prepare two‐layered bimetallic heterojunction with porous structures. This concept is successfully applied in fabrication of flexible electrode based on CuO‐Co(OH)2 lamella on Cu‐plated carbon cloth (named as CPCC@CuO@Co(OH)2). The unique structure brings the electrode a high specific capacity of 3620 mF cm−2 at 2 mA cm−2 and appropriate mechanical properties with Young's modulus of 302.0 MPa. Density functional theory calculations show that porous heterojunction provides a higher intensity of electron state density near the Fermi level (E–Ef = 0 eV), leading to a highly conductive CPCC@CuO@Co(OH)2 electrode with both efficient charge transport and rapid ion diffusion. Notably, the supercapacitor assembled from CPCC@CuO@Co(OH)2//CC@AC shows high energy density of 127.7 W h kg−1 at 750.0 W kg−1, remarkable cycling performance (95.53% capacity maintaining after 10 000 cycles), and desired mechanical flexibility. The methodology and results in this work will accelerate the transformative developments of flexible energy storage devices in practical applications.

Flexible asymmetric supercapacitor (FASC) systems are expected to exhibit not only excellent energy storage properties and safety but also satisfactory flexibility and robust integration. However, tremendous issues such as low capacitance, narrow voltage window, and poor mechanical properties still exist. In this paper, a novel kind of 3D lamellar Mn(OH) 2 nanosheets on Cu-plated carbon cloth with a core-shell integrated framework (CPCC@CuO@Mn(OH) 2 ) is fabricated to obtain the flexible material in the FASC. In this unique CPCC@CuO@Mn(OH) 2 electrode material, the high theoretical specific capacity of CuO and Mn(OH) 2 brings superior energy storage properties. Meanwhile, as the shell part, the deposited Mn(OH) 2 layer and coated CuO layer work as both capacity contributors and substrate protectors, simultaneously maintaining the high capacitance and satisfactory flexibility of the electrodes. Therefore, the capacitance successfully achieves around 8140 mF cm −2 under 0.5 mA cm −2 . Significantly, the assembled FASC (named as CPCC@CuO@Mn(OH) 2 //CC@AC) achieves a working voltage of up to 2.4 V. In the case of a high-power density close to 34.31 mW cm −3 , its energy density reaches around 6.29 mW h cm −3 . Moreover, the capacity holds 88.9% even after 10,000 cycles, showing its great application potential in the field of wearable electronics.

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Preparation of a material with excellent rate performance and high capacity contribution is significant for sodium-ion hybrid capacitors (SIHCs). TiO2 has been extensively studied due to its outstanding chemical stability,...