Asymmetric Solid-State Supercapacitor Devices Made of Recycled Lithium-Ion Batteries and Palm Loofah Fibers with Exceptional Stability and Energy Density

Green solid-state supercapacitors are becoming essential, especially with the increasing demand for energy storage devices. However, the acute desire for electronic devices has led to a surge in electronic waste, which affects the environment, human health, and economy. In this regard, we demonstrate the ability to repurpose recovered materials to fabricate highly compatible solid-state supercapacitor devices. Valuable metals from battery waste (M-BW) are recovered, purified through a straightforward hydrometallurgical method, and reused efficiently as positive electrodes in supercapacitor applications. Furthermore, the potential of carbon recycled from agriculture waste (C-AW) is explored as a carbonaceous material for supercapacitor negative electrodes. The morphological and compositional analyses of both recycled materials were characterized using field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. Then, M-BW was combined with C-AW to fabricate a hybrid solid-state supercapacitor device (M-BW//C-AW) and tested electrochemically. The device displays high specific capacitance (60 F g–1) and succeeds in providing high energy and power densities (31 Wh kg–1 at 875 W kg–1). Furthermore, it achieves superior stability with up to 50 000 cycles of charges and discharges, indicating its ability to efficiently store and deliver electrical energy with a capacitance retention rate of 100%.