Oxygen-rich hierarchically porous carbons derived from pitch-based oxidized spheres for boosting the supercapacitive performance
Oxygen-rich hierarchically porous carbons derived from pitch-based oxidized spheres for boosting the supercapacitive performance
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源自沥青基氧化球的富氧分级多孔碳可提高超级电容性能
DOI：
10.1016/j.jcis.2019.01.038
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发表时间：
2019
影响因子：
9.9
通讯作者：
Li Kaixi
中科院分区：
文献类型：
--
作者：
Zhang Dongdong;He Chong;Wang Yuzi;Zhao Jianghong;Wang Jianlong;Li Kaixi
采用一步KOH活化沥青基氧化球（POS）作为碳前驱体制备了富氧分层多孔碳。活化温度不仅可以定向调整碳的孔隙度，而且可以保证POS中保留适度的氧官能团，这有利于在一个电极上有效地集成双电层电容和伪电容。所制备的沥青基活性炭（PAC）具有2245 m2g−1的高比表面积，微孔发育良好，中、大孔合适，富氧掺杂率为15.9 at%。得益于层次化孔隙度和假电容氧基团的协同作用，PAC的比电容分别为427F g−1和302F g−1，分别为0.5 A g−1和50 A g−1，在6 M KOH电解质的三电极体系中，其电容保持率为71%。此外，组装后的对称超级电容器在功率密度为9918 W kg−1时显示出5.79 Wh kg−1的高能量，具有良好的循环稳定性，在5 a g−1时，循环10,000次后电容保持率为95%，高于商用Kuraray YP-50F。这一发现表明，一步KOH活化与富氧沥青相结合可能是一种最佳的组分，可以精细地定制活性炭的孔隙度和氧掺杂，用于储能应用。
Oxygen-rich hierarchically porous carbons are prepared by employing one-step KOH activation of pitch-based oxidized spheres (POS) as carbon precursors. The activation temperatures not only allow directed tailoring the porosity of carbon but also guarantee the preservation of moderate oxygen functional groups from POS, which are beneficial for efficiently integrating the electrical double layer capacitance and pseudocapacitance in one electrode. The as-prepared pitch-based activated carbons (PAC) possesses a high specific surface area of 2245 m2g−1with well-developed micropores, appropriate meso-macropores, and rich oxygen doping of 15.9 at%. Benefiting from the synergistic effect of hierarchical porosity and pseudocapacitive oxygen groups, PAC exhibit high specific capacitance of 427F g−1and 302F g−1at 0.5 A g−1and 50 A g−1, respectively, as well as excellent capacitance retention of 71% in a three-electrode system with 6 M KOH electrolyte. Moreover, the as-assembled symmetrical supercapacitor displays a high energy of 5.79 Wh kg−1at a power density of 9918 W kg−1with excellent cycling stability with capacitance retention of 95% at 5 A g−1after 10,000 cycles, which is higher than that of commercial Kuraray YP-50F. This finding demonstrates that one-step KOH activation coupled with oxygen-rich pitch may act as an optimal component to finely tailor the porosity and oxygen doping on activated carbons for energy storage applications.