Hierarchical porous activated carbon for supercapacitor derived from corn stalk core by potassium hydroxide activation

Abstract

Hierarchical porous activated carbon (AC) was obtained from corn stalk pith with a hierarchical macroporous nature, which is composed of cells of soft and spongy texture. The high specific surface area (2495 m 2 g-1) of the activated carbon (AC) was produced by the activation of corn stalk core (CSC) using potassium hydroxide at 700 °C. SEM, TEM and XRD were used to test the microstructure and crystallographic orientation of the carbon samples. The cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy were measured based on CSC-700. This sample had relatively low inner resistance of 1.0 Ω. The specific capacitance was 323 F g-1 in 6 mol L-1 KOH electrolyte at a current density of 0.1 A g-1 , and it still maintained very good cyclic stability with capacitance retention ratio of 97.9% (from 265.0 to 262.4 F g-1) at current density of 1.0 A g-1 for 1000 cycles.

B, N-dual doped sisal-based multiscale porous carbon for high-rate supercapacitors

“…13,14 To solve these problems, efforts have been devoted on novel preparation methods combining various pretreatment processes and common activation to produce ACs with both high SSA and high ratio of mesopores, thus resulting in high specic capacitance and high rate performance. [15][16][17][18][19] For example, through combining hydrothermal and KOH activation, ACs with high SSA (3037 m 2 g À1 ) and high mesoporosity (>82%) were prepared from lotus pollen, and exhibited a high capacitance of 207 F g À1 and superior capacitance retention of about 190 F g À1 at 10 A g À1 . 10 However, in spite of the ratios of meso/micropore are tunable in these novel ACs, the disordered pore structures with randomly distributed mesopores and micropores still hinder the full utilization of all-level pores.…”

“…45,46 Different from various natural bers such as jute, ax, hemp, cotton and ramie, sisal bers are especially characterized with honeycomb texture constructed by abundant parallel distributed tracheids. [15][16][17] The unique honeycomb structure is quite benecial for the development of hierarchical porous structure, while previous studies merely employed sisal bers as common precursors of ACs. 44,46,[48][49][50] Herein, for the rst time, we report a novel method to prepare B, N dual-doped ACs with multiscale porous structure from sisal bers for highperformance EDLCs.…”

Preparation of activated biomass carbon from pine sawdust for supercapacitor and CO 2 capture

“…However, CO was still released out when the activation temperature was maintained at 900°C for 2 hours. The metallic K and CO can be obtained by K compounds (K 2 O and K 2 CO 3 ) reduced by biomass carbon (Equation ) . The metallic potassium becomes vapor at high temperature, and easily intercalate and diffuse into the carbon lattices, leading to much developed porosity structure.…”

“…The metallic K and CO can be obtained by K compounds (K 2 O and K 2 CO 3 ) reduced by biomass carbon (Equation (7) and (8)). 30 The metallic potassium becomes vapor at high temperature, and easily intercalate and diffuse into the carbon lattices, leading to much developed porosity structure. Table 2 compares the ultimate analysis results of the BC-700 and ABC samples.…”

Facile and Flexible Preparation of Highly Active CuCe Monolithic Catalysts for VOCs Combustion

“…The created oxygen vacancy can improve the catalytic activity. The isotherm curve was a typical IV curve with an obvious H4‐type hysteresis loop (Figure i) . The BJH pore size was 3.4 nm, indicating the formation of the mesopores of the CuCe catalyst (Figure j).…”