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Herein, a novel asymmetric supercapacitor (ASC) with high energy density is fabricated based on the NiSe@MoSe2 nanosheet arrays and the nitrogen-doped pomelo mesocarps-based carbon nanosheet (N-PMCN) as a positive electrode and a negative electrode, respectively. The novel NiSe@MoSe2 nanosheet arrays are designed and prepared by a facile one-step hydrothermal growth method from nickel foam as a nickel precursor and nucleation framework. The N-PMCN is prepared using simultaneous CaCl2 activation and urea nitrogen-doped processes from thepomelo mesocarps as a biomass-based carbon precursor. Because of the unique nanosheet array architecture of NiSe@MoSe2 and interconnected sheet-like porous morphology with high nitrogen content (∼9 wt %) of N-PMCN, they exhibit a maximum specific capacity of 128.2 mAh g–1 and high specific capacitance of 223 F g–1 at a current density of 1 A g–1. Moreover, the assembled novel NiSe@MoSe2//N-PMCN ASC device with a maximum operating voltage of 1.65 V has demonstrated a high energy density of 32.6 Wh kg–1 at a power density of 415 W kg–1 and outstanding cycling stability with 91.4% capacitance retention after 5000 cycles in aqueous electrolyte.

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Two-dimensional conducting polymers nanosheet prepared by the soft-template-assisted technique in aqueous system still has rarely been reported, especially the formation of nanosheets structure by protonic acid assisted controlling the stability of the micelles method. Herein, a facile, one-step, bottom-up approach is developed to synthesize novel and uniform conductive poly­(4-aminodiphenylamine) (P­(4-ADPA)) nanosheets with controlled morphology via regulating the proton acid concentration during the self-assembly of surfactant lamellar micelles. The as-produced conducting P­(4-ADPA) demonstrates a integral nanoframework structure with uniform and intertwined nanosheets, resulting in a satisfactory specific capacitance of 395 F g–1 at the current density of 0.5 A g–1. Furthermore, another pseudocapacitor electrode material, urchin-like W18O49, is selected as a negative electrode material to fabricate a novel P­(4-ADPA)//W18O49 asymmetric supercapacitor, which extends the operating voltage window up to 1.5 V, provides an energy density of 24.4 W h kg–1 at a high power density of 1491 W kg–1, and possesses superlong-life of 92% capacitance retention after 10 000 cycles. Therefore, the present work will propose an affordable strategy to design novel conducting polymer nanosheets and open up the possibility of cheap conductive polymers to meet the demands of energy storage.