Catalysis

Adsorption

Composite number

Engineering

Capacitance

Biology

Electrochemistry

Materials science

Carbon fibers

Chemical engineering

Food science

Activated carbon

Porosity

Physical chemistry

Supercapacitor

Organic chemistry

Hibiscus sabdariffa

Biomass (ecology)

Agronomy

Carbonization

Environmental science

Composite material

Environmental protection

Chemistry

Scanning electron microscope

Active carbon

Electrode

Specific surface area

RSC Advances

Carbon-based materials are manufactured as high-performance electrodes using biomass waste in the renewable energy storage field. Herein, four types of hierarchical porous activated carbon using hibiscus sabdariffa fruits (HBFs) as a low-cost biomass precursor are synthesized through carbonization and activation. NH4Cl is used as a chemical blowing agent to form carbon nanosheets, which are the first types of hibiscus sabdariffa fruit-based carbon (HBFC-1) sample, and KOH also forms a significant bond in the activation process. The prepared HBFC-1 is chosen to manufacture the symmetric supercapacitor due to its rough surface and high surface area (1720.46 m2 g-1), making it show a high specific capacity of 194.50 F g-1 at a current density of 0.5 A g-1 in a three-electrode system. Moreover, the HBFC-1 based symmetric supercapacitor devices display a high energy density of 13.10 W h kg-1 at a power density of 225.00 W kg-1, and a high specific capacity of 29 F g-1 at 0.5 A g-1. Additionally, excellent cycle life is observed (about 96% of capacitance retained after 5000 cycles). Therefore, biomass waste, especially hibiscus sabdariffa fruit based porous carbon, can be used as the electrode for high-performance supercapacitor devices.

Synthesis of porous carbon material based on biomass derived from hibiscus sabdariffa fruits as active electrodes for high-performance symmetric supercapacitors