A High‐Energy Asymmetric Supercapacitor Based on Tomato‐Leaf‐Derived Hierarchical Porous Activated Carbon and Electrochemically Deposited Polyaniline Electrodes for Battery‐Free Heart‐Pulse‐Rate Monitoring

Abstract

A simple and scalable method to fabricate a novel high‐energy asymmetric supercapacitor using tomato‐leaf‐derived hierarchical porous activated carbon (TAC) and electrochemically deposited polyaniline (PANI) for a battery‐free heart‐pulse‐rate monitor is reported. In this study, TAC is prepared by simple pyrolysis, exhibiting nanosheet‐type morphology and a high specific surface area of ≈1440 m2 g−1, and PANI is electrochemically deposited onto carbon cloth. The TAC‐ and PANI‐ based asymmetric supercapacitor demonstrates an electrochemical performance superior to that of symmetric supercapacitors, delivering a high specific capacitance of 248 mF cm−2 at a current density of 1.0 mA cm−2. The developed asymmetric supercapacitor shows a high energy density of 270 µWh cm−2 at a power density of 1400 µW cm−2, as well as an excellent cyclic stability of ≈95% capacitance retention after 10 000 charging–discharging cycles while maintaining ≈98% Coulombic efficiency. Impressively, the series‐connected asymmetric supercapacitors can operate a battery‐free heart‐pulse‐rate monitor extremely efficiently upon solar‐panel charging under regular laboratory illumination.

Date Leaves-Derived Submicron/Nano Carbon-Modified Glassy Carbon Electrode for Highly Sensitive and Simultaneous Detection of 1-Naphthol and 2-Naphthol

“…Preparation of DLSNC.-The DLSNC utilized in this study was prepared following the method detailed in our previous work. 54,55 The process began by thoroughly washing palm date leaves with a cleaning agent and rinsing with deionized (DI) water. The leaves were then left to dry in Sunlight for several days.…”

“…50 This biomass can be transformed into carbon materials for the fabrication of lowcost, effective devices, such as electrochemical sensors [51][52][53][54] and energy storage devices. [55][56][57][58] Despite advances in sensor technology z E-mail: abetar@kfupm.edu.sa; maziz@kfupm.edu.sa Journal of The Electrochemical Society, 2024 171 047505 for detecting phenolic chemicals, present approaches have significant drawbacks, including high prices, complex fabrication procedures, low sensitivity and selectivity, and environmental concerns about their creation and disposal. 59 These difficulties underscore the need for more sustainable and environmentally friendly solutions.…”

A Ti3C2Tx@PANI core–shell heterostructure assembled into a 3D porous hydrogel as a free-standing electrode for high-energy supercapacitors

“…This effectively increases the interlayer spacing, provides abundant ion/electron transport channels and active sites, and dramatically boosts the electrochemical reaction kinetics. [40][41][42] Notably, the resultant fibershaped polyaniline (PANI) possesses large relative molecular mass, 43,44 and can store a large amount of charge under an electric field through fast invertible doping and dedoping redox reactions of p-type or n-type elements. 45,46 GO is a hexagonally arranged layered material with oxygen-containing functional groups mainly composed of a single layer of carbon atoms, and has a reliable EDLC.…”

Metal Negatrode Supercapatteries: Advancements, Challenges, and Future Perspectives for High‐Performance Energy Storage

“…Energy storage is crucial in meeting the rising demands for efficient and sustainable energy systems. As the world grapples with the challenges of global warming, there is an urgent need for innovative energy storage technologies and materials devoid of greenhouse gas emissions [4–6] . Electrochemical energy storage (EES) technologies, including supercapacitors and batteries, emerge as potential contenders in energy storage solutions.…”

“…The assessment of energy storage devices hinges on several pivotal criteria: specific energy, specific power, and cycle life. Predominant research efforts have been channelled towards augmenting the energy and power densities of these devices while simultaneously extending their operational lifespan [5,14,15] . As a result, a new strategy for integrating supercapacitors and batteries into a single device has been proposed.…”