Properties of Porous Carbon Derived from Cornstalk Core in High‐Performance Electrochemical Capacitors

Abstract

Cornstalk core, a renewable by‐product of agriculture, has been used as a carbon precursor to prepare high‐performance electrode materials used in electrochemical capacitors (ECs). The influences of temperature and the ratio of activator (KOH) to carbon (mKOH/mC) on the structures of porous carbon materials (PCMs) derived from cornstalk core have been investigated systematically. The PCM obtained at optimal conditions (mKOH/mC=6, activated at 800 °C) exhibits a porous structure with a large specific surface area of 2139 m2 g−1 and total pore volume of 1.16 cm3 g−1. Acting as an electrode material, the optimum PCM exhibits excellent capacitive performance with a specific capacitance of 317.0 F g−1 at a scan rate of 1 mV s−1. More promising, a high power density of 28.3 kW kg−1 and energy density of 6.8 Wh kg−1 are achieved in 6 mol L−1 KOH aqueous electrolyte, as well as high‐rate capability and excellent cycling stability. The capacitor has a time constant of about 0.3 s, and could retain more than 93 % of its initial capacitance after 10 000 cyclic processes. This work proposes a potential biomass resource to produce effective porous carbons for high‐performance ECs.

Porous Carbons: Structure‐Oriented Design and Versatile Applications

“…In addition, many natural biomass materials contain heteroatoms like N, which can be partially retained in the resulting carbon, helping to improve the electrical conductivity or catalytic activity. [ 208,240 ] Carbonaceous materials have been demonstrated to be produced from a wide range of biomass materials including lignin, [ 241 ] corncob, [ 242 ] ginkgo leaves, [ 243 ] cornstalk, [ 244 ] bacterial cellulose, [ 245 ] banana peel, [ 193 ] peanut shells, [ 246 ] willow catkins, [ 211 ] pinecone hull, [ 247 ] bamboo chopsticks, [ 248 ] Camellia japonica, [ 49c ] pine core shells, [ 44b ] and so forth.…”

Biomass-derived carbon materials with structural diversities and their applications in energy storage

“…The as-prepared carbon has highly interconnected pores with the pore size of about 0.5-1 nm, high micropore volume ratio of 83% and large surface area of about 1069 m 2 g −1 . Moreover, the biomass-derived carbon materials with abundant micropores can also be prepared from ginkgo leaves [101], cotton stalk [102], pine needles [103], acacia gum [104], pomelo peel [105] popcorn [106], cornstalk [107], walnut shell [108]. Furthermore, microporous surface area and pore volume depend on the amount of KOH and heat treatment temperature [42,102,104].…”

Biomass-derived nitrogen-doped hierarchical porous carbon as efficient sulfur host for lithium–sulfur batteries

“…By contrast, carbon materials derived from biomass deliver highly attractive advantages of simple preparation and good cost effectiveness [15] . Beyond that, unique morphological architectures and structural characteristics can be obtained for biomass-derived carbons from varied origins [16] , such as banana peel, cherry stone, cornstalk, peanut shell, and bean dregs [17][18][19][20] . Thus, it is highly desired that carbon materials derived from wellselected biomass could construct a favorable sulfur host for the significant improvement of Li-S battery performance.…”