Potassium sulphate (K₂SO₄) activation of chestnut shell to oxygen‐enriched porous carbons with enhanced capacitive properties

Abstract

Noncorrosive K 2 SO 4 is found to be able to activate the chestnut shell carbon to oxygen-enriched porous carbons. Chestnut shells are activated by K 2 SO 4 . The structure, texture, chemical state of surface of samples and morphology are analyzed via X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, transmission electron microscopy and scanning electron microscopy, respectively. With the optimum amount of K 2 SO 4 (m(K 2 SO 4 )/m(C) = 1.8), higher specific surface area (SSA, 1412 m 2 g −1 ) and total pore volume (0.75 m 2 g −1 ) are obtained. The prepared carbon samples exhibit a hierarchical textural structure making up of micropores, mesopores and macropores. More importantly, a large amount of oxygen defects, as high as 37.7%, and a small amount of sulfur element (0.31%-0.79%) are successfully introduced on the surface of the carbons. The activation mechanism of K 2 SO 4 is also investigated via thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC), which put it down to the high-temperature redox reaction between C and K 2 SO 4 . Owing to the high SSA, the composition of pore, and the abundant surface defects, the activated porous carbons originated from chestnut shell carbon possess highly enhanced capacitive properties. At 0.1 A/g, the specific capacitance reaches 265 F/g, and retains 92% of its starting value after 10 000 cycles at 10 A/g. In general, K 2 SO 4 is a promising noncorrosive alternative to the conventional KOH activator. K E Y W O R D Sactivator, chestnut shell, K 2 SO 4 , oxygen defect, porous carbon, supercapacitor

Chestnut-Derived Activated Carbon as a Prospective Material for Energy Storage

“…However, as mentioned above, our C–KOH sample is characterized by outstanding rate capability, which is crucial for the high-power application. The energy density values achieved for our chestnut seed-derived AC are average compared to AC derived from chestnut [ 31 , 33 , 34 , 39 , 55 ], as shown in Ragone plot ( Figure 9 ). However, the energy and power densities should be calculated for the system, which is close to a real device as they are essential parameters from the technological point of view.…”

“…Therefore, it is crucial to investigate a whole range of different biomass wastes, optimize the thermal treatment parameters, select appropriate activation method and optimize its conditions [ 5 ]. Recently, a number of species, such as agricultural and forestry biomass [ 23 , 24 ], soybean pod [ 25 ], castor shell [ 26 ], waste biomass [ 27 ], durian husk [ 28 ], cassava stalks and bamboo [ 29 ], rice straw [ 30 ], chestnut shell [ 12 , 31 , 32 , 33 , 34 , 35 , 36 ] and water chestnut ( Eleocharis dulcis ) [ 37 , 38 ] have been investigated as porous carbon precursors for energy storage application.…”

“…The resulted AC showed SSA up to 1987 m 2 g −1 , which resulted in the capacitance value of 105.4 F g −1 . Potassium sulphate as the activating agent was used by Hong et al for preparation of chestnut shell-derived AC [ 34 ]. This led to AC with a specific surface area of 1412 m 2 g −1 and capacitance value equal to 265 F g −1 at a relatively low current density of 0.1 A g −1 .…”

Porous bamboo‐like CNTs prepared by a simple and low‐cost steam activation for supercapacitors

“…16 Chestnut shell-derived ACs synthesized by a mild activating agent K 2 SO 4 reached a specific capacity of 216 F g −1 at 0.2 A g −1 . 17 Chitin-based ACs prepared by CuCl 2 Á2H 2 O as theactivator exhibited a specific capacity of 227 F g −1 at 0.5 A g −1 and a retention of 67.7% even at 50 A g −1 . 18 Guardia et al proved that the synergy between GO and carbon particles by KOH activation allowed their composite to obtain a specific capacity of 260 F g −1 at 1 mA cm −2 .…”

Porous activated carbon monolith with nanosheet/nanofiber structure derived from the green stem of cassava for supercapacitor application

“…27,28 These characteristics promote the accessibility of large effective surface, required to improve specific capacitance. 24,29 Meanwhile, some biomass had been reported as successful and effective precursors in the production of activated carbon electrode, derived from agricultural waste, 30 industrial corps, 31 leaves, [32][33][34] fruit peels, 7,35 fruit shell, 36 flower, 6,37 fruit seeds, 38 stem, 39 wood, 40,41 milk, 42 bagasse. 43,44 An alternative biomass material is cassava (Manihot esculenta), which originates from the tropical countries, including Indonesia.…”