High Rate Performance Supercapacitors Based on N, O Co-Doped Hierarchical Porous Carbon Foams Synthesized via Chemical Blowing and Dual Templates

Abstract

N, O Co-Doped porous carbon materials are promising electrode materials for supercapacitors. However, it is still a challenge to prepare high capacitance performance N, O Co-Doped porous carbon materials with balanced pore structure. In this work, a simple chemical blowing method was developed to produce hierarchal porous carbon materials with Zn(NO3)2·6H2O and Fe(NO3)3·9H2O as the foaming agents and precursors of dual templates. Soybean protein isolate served as a self-doping carbon source. The amount of Fe(NO3)3·9H2O influenced the microstructure, element content and capacitance performance of the obtained porous carbon materials. The optimized sample CZnFe-5 with the addition of 5% Fe(NO3)3·9H2O displayed the best capacitance performance. The specific capacitance reached 271 F g−1 at 0.2 A g−1 and retained 133 F g−1 at 100 A g−1. The CZnFe-5//CZnFe-5 symmetric supercapacitors delivered a maximum energy density of 16.83 Wh kg−1 and good stability with capacitance retention of 86.33% after 40,000 cycles tests at 50 A g−1. The symmetric supercapacitors exhibited potential applications in lighting LED bulbs with a voltage of 3 V. This work provides a new strategy for the synthesis of hierarchical porous carbon materials for supercapacitors from low-cost biomass products.

Effect of the Nature of the Electrolyte on the Behavior of Supercapacitors Based on Transparent ZnMn2O4 Thin Films

“…The surface appears more textured and lacks the circular surface marks of spray droplets. This change in the surface texture is produced through chemical modification of the ZnMn2O4 according to Equations (7) and (8). The SEM-EDS images of the cycled electrode show holes corresponding to local loss of the electrode material (Figure 6a,b).…”

“…The SEM image (Figure 10a) shows a more textured surface than the original electrode surface (Figure 3a), with spray droplet marks still visible after 300 CV cycles. No loss of electrode material in the form of voids is observed (Figure 10a), which may be due to a lower solubility of Zn and Mn in the PVP-ionic liquid electrolyte than in the aqueous Na2SO4 electrolyte, favoring the reversibility of the reactions described in Equations ( 7) and (8). The EDS mappings of Mn and Zn (Figure 10b-f) show that both elements are present and homogenously distributed on the surface and in the cross-section.…”

Coatings on Lithium Battery Separators: A Strategy to Inhibit Lithium Dendrites Growth

“…The researchers explored the possibility of replacing the graphite anode with a silicon anode, but because the huge volume expansion and contraction of the silicon anode can cause the electrode to powder, they combined silicon with carbon to inhibit it [12][13][14]. Tin-based negative [15,16], sodium-ion batteries [17,18], zinc-ion batteries [19,20], and capacitive energy storage devices have also been proposed by researchers to replace lithium-ion batteries to relieve energy pressure [21,22]. With its extra-high capacity (3860 mAh g −1 ) and the lowest negative electrochemical potential (−3.040 V), Li metal is regarded as the "Holy Grail" electrode and receives extensive research attention.…”