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The photo‐rechargeable supercapacitor enables the self‐powering of flexible wearable electronics. However, flexible wearable electronics require supercapacitors not only with excellent flexibility but also with high energy density. P‐diaminoazobenzene (P‐Azo) as a new type of organic electrode material with NN is directly connected to the benzene ring and forms a large π‐conjugated system, which makes it have a lower lowest unoccupied molecular orbital (LUMO) energy level, is beneficial to transfer of electrons, and increases the conductivity of organic molecules. In addition, NN can realize the transfer of two electrons, which makes P‐Azo have a higher energy density. Asymmetric flexible supercapacitors are fabricated by assembling P‐Azo, activated carbon, and an adhesive electrolyte, with 425.2 mW h cm−2 (55.19 Wh kg−1) energy density at a power density of 80 mW cm−2 (10.38 W kg−1), and 90.7% capacitance retention after 80 000 cycles of bending. In this work, supercapacitors and perovskite submodules are coupled to prepare a photo‐rechargeable supercapacitor to achieve a 7% overall energy‐conversion efficiency. Therefore, this supercapacitor paves a practical route for powering future wearable electronics. [ABSTRACT FROM AUTHOR]

Photorechargeable supercapacitors are perfect energy storage devices, particularly for solar cells that output electricity only during sunshine hours. The lower energy density of supercapacitors is due to fewer redox‐active sites, poor electrolyte accessibility at the electrodes, and charge loss during charge transfer from solar cells to the supercapacitor. Here, an electrolyte‐accessible organic–inorganic hybrid electrode with synergistic pseudocapacitance of Ti3C2Tx and high theoretical specific capacity CO active centers to enhance the energy density of the supercapacitor is proposed. Density functional theory (DFT) calculations show that the covalent cross‐linking of organic molecules changes the charge density redistribution of Ti3C2Tx, enhances ion absorption and storage, and increases the energy density of the supercapacitors. Based on these DFT calculation results, hybrid electrodes are successfully prepared using p‐phenylene diisocyanate to covalently cross‐link pseudocapacitors Ti3C2Tx with anthraquinone such as 1‐hydroxyanthraquinone (HA) or 1‐amino‐4‐bromoanthraquinone‐2‐sodium sulfonate (ABS). The Ti3C2Tx‐HA hybrid electrodes exhibit high areal specific capacity (2532.5 mF cm−2), excellent ion absorption storage capability, and long‐term stability. The asymmetric supercapacitor yields a decent area specific capacity (1686.72 mF cm−2 at 0.25 mA cm−2) and energy density (599.72 mWh cm−2 at a power density of 200 mW cm−2). These high‐energy‐density supercapacitors are coupled with perovskite solar cells to prepare photorechargeable supercapacitors with fast energy storage. [ABSTRACT FROM AUTHOR]

• Electrostatic anchoring in situ polymerization synthesizes hybrid electrode materials. • MXene collaboratively with high Th loading enhances specific capacity and cycle stability. • Combining supercapacitors with perovskite solar cells achieves rapid charge storage. Portable photorechargeable supercapacitors hold great promise as ideal power sources for future IoT applications. However, the widespread implementation of supercapacitors is hindered by their suboptimal energy density. Organic electrodes, with their high specific capacity, have become rising stars in the energy storage community. Herein, we pioneer an electrostatic-anchoring in situ polymerization reaction pathway to synthesize MXene-organic hybrid electrode materials. Theoretical calculations show that thionine (Th) is the optimal candidate for grafting onto the pseudocapacitive 2D MXene due to its low energy levels, narrow band gap, and multiple active sites. Multilevel interactions between Th and MXene are established to prevent Th from dissolution, to inhibit the MXene from restacking, and to facilitate electron accumulation in Th, thus enhancing the accessibility/absorption of ions in electrolytes and electrode stability. The hybrid electrodes exhibit a specific capacity as high as 4906.7 mF/cm2 at 1 mA cm−2; more importantly, an integrated asymmetric flexible supercapacitor displays high specific capacity (3183.1 mF/cm2) and large energy density (1432.4 mWh/cm2), all three values are the highest among their respective categories. Combining supercapacitors with all-inorganic perovskite solar cells to achieve rapid charge storage. [ABSTRACT FROM AUTHOR]

Abstract Co(OH) 2 @FeCo 2 O 4 nanocomposite was successfully synthesized via a facile one-step hydrothermal reaction without thermal treatment. The structure and chemical composition of as-synthesized Co(OH) 2 @FeCo 2 O 4 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. The results show the FeCo 2 O 4 nanosheets are covered with the Co(OH) 2 nanoparticles and the BET show the nanocomposite possess the mesoporous structure with specific surface area and total pore volume are 93.071 m2 g−1 and 0.37 cm3 g−1, respectively. In addition, the electrochemical performances were investigated in a three-electrode system to evaluate the material. The as-synthesized Co(OH) 2 @FeCo 2 O 4 nanocomposite exhibits a high specific capacitance of 1173.43 F g−1 at 1 A g−1 and remarkable cycling stability with 95.4% capacitance retention after 5000 cycles. The results show the higher capacitance and longer cycle performance, compared with the Co(OH) 2 and FeCo 2 O 4 , respectively. This remarkable electrochemical performances were mainly due to mesoporous structure and the synergistic effect of Co(OH) 2 and FeCo 2 O 4. It means that this nanostructure Co(OH) 2 @FeCo 2 O 4 synthesized by this simple and cost-effective method would have more hopeful prospects in energy storage applications. Graphical abstract Co(OH) 2 @FeCo 2 O 4 nanocomposite applied as electrode of supercapacitor shows an impressive enhancement of the performance including the areal capacitance and cycling stability. Image 1 [ABSTRACT FROM AUTHOR]

Cerium oxide nanoparticles/multi-wall carbon nanotubes (MWCNTs) composites are synthesized by a facile hydrothermal method without any surfactant or template. The morphology and microstructure of samples are examined by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Electrochemical properties of the MWCNTs, the pure CeO 2 , and the CeO 2 /MWCNTs nanocomposites electrodes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GDC) and electrochemical impedance spectroscopy (EIS) measurements. The CeO 2 /MWCNTs nanocomposite (at the mole ratio of 1:1) electrode exhibits much larger specific capacitance compared with both the MWCNTs electrode and the pure CeO 2 electrode and significantly improves cycling stability compared to the pure CeO 2 electrode. The CeO 2 /MWCNTs nanocomposite (at the mole ratio of 1:1) achieves a specific capacitance of 455.6 F g −1 at the current density of 1 A g −1 . Therefore, the as prepared CeO 2 /MWCNTs nanocomposite is a promising electrode material for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]