Ultrafast flashlight sintered mesoporous NiO nanosheets for stable asymmetric supercapacitors

Abstract

Ultrafast flashlight sintering (FLS) has become an important green manufacturing technology for the structural reformation of various nanomaterials. Nickel oxide (NiO) has been extensively studied as a promising electrode material for electrochemical energy storage owing to its high theoretical specific capacitance, low cost, and appropriate chemical compatibility. This study reports the fabrication of mesoporous ultrathin NiO nanosheets on carbon cloth (CC) as green electrodes for flexible supercapacitors (SCs) through an exceptional ultrafast millisecond FLS process at room temperature. The optimized FLS-NiO@i12J electrode exhibited a remarkable specific capacity of 202.3 mA h g−1 (1215 F g−1) at a current density of 2 A g−1. Strikingly, the as-fabricated FLS-NiO electrodes outperformed the time and energy-consuming conventional thermally annealed (CTA) NiO electrodes. Furthermore, the flexible FLS-NiO@i12J//rGO asymmetric SCs deliver a remarkable energy density of 47.18 Wh kg−1 at a power density of 758.37 W Kg−1 and extraordinary cycling stability performance after 15,000 cycles. In addition, the FLS-NiO@i12J electrodes offer unique mesoporous structures, high surface areas, and numerous open-pore channels of ultrathin NiO nanosheets that facilitate fast transport of ions and rapid redox reactions. Thus, the present approach is promising for designing advanced electrode materials for flexible energy storage applications.