Highly active N, S Co-Doped Ultramicroporous Carbon for High-Performance Supercapacitor Electrodes

Abstract

N, S-doped ultramicroporous carbons (NSUC-x) with a high nitrogen/sulfur content and a narrow pore-size distribution of around 0.55 nm were firstly prepared using L-cysteine as a nitrogen and sulfur source. The phase, graphitization degree, morphology, specific surface area, pore structure and surface condition of NSUC-x are investigated to analyze the key role in electrochemical performance. Such an ultramicroporous structure and N, S doping not merely provide a high-specific surface area and a suitable pore size, but also induce a good wettability for the fast transport and adsorption of electrolyte ions. Due to the above strategies, the typical NSUC-0.4 exhibits a high gravimetric capacitance of 339 F g−1 at 0.5 A g−1 as well as a capacity retention of 91.6% after 10,000 cycles in a three-electrode system using a 6 M KOH electrolyte. More attractively, a NSUC-0.4-assembled symmetrical supercapacitor delivers an energy output of 7.4 Wh kg−1 at 100 W kg−1 in 6 M KOH as well as a capacity retention of 92.4% after 10,000 cycles, indicating its practical application prospect. Our findings open up new prospects for the design and electrochemical application of N, S-doped ultramicroporous carbons.

Horseshoe-shaped Hollow Porous Carbon: Synthesis by Hydrothermal Carbonization with Dual-template and Electrochemical Property

“…RI [43][44] ，HNCS-1.25-18 的 RI(0.44 [46][47] 。图 7(e)为不同 样品的 Nyquist 曲线，曲线与 x 轴的交点代表材料的等效 串联内阻 RS，RS 主要包括电解液的电阻、电极材 料自身的电阻和接触电阻等 [43][44] 。HNCS-1.25-12 具有最小的等效串联电阻值(0.45 Ω)，说明其电荷 传输速率最快，损耗最低。高频区半圆的直径代表 电 解液与 材料接触 界面的 电荷转移 电阻 RCT， HNCS-1.25-12 的半圆直径最小， 表明其电荷在电解 液与材料表面处转移阻力最小 [48] 。中频区域的 [49] 。 此外， 由图 7(f)可知 HNCS-1.25-12…”

Facile Synthesis of Functionalized Porous Carbon by Direct Pyrolysis of Anacardium occidentale Nut-Skin Waste and Its Utilization towards Supercapacitors

“…Supercapacitors can be classified into two main categories based on the energy storage mechanism of electrode materials: electric double-layer (EDL) capacitors and pseudocapacitors [ 4 , 10 ]. Energy is stored through electrostatic accumulation of charges at the electrode–electrolyte interfaces in EDL capacitors and by fast Faradaic reactions between the electrode and electrolyte [ 11 ]. Supercapacitors typically consist of three major parts: (i) electrolyte, (ii) electrode, and (iii) separator.…”