Ran Fen, Wu Yage, Jiang Minghuan, Tan Yongtao, Liu Ying, Kong Lingbin, Kang Long, Chen Shaowei
State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, P. R. China.
Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, California 95064, USA.
Dalton Trans. 2018 Mar 28;47(12):4128-4138. doi: 10.1039/c7dt04432a. Epub 2018 Feb 22.
In this study, a hybrid electrode material for supercapacitors based on hierarchical porous carbon fiber@vanadium nitride nanoparticles is fabricated using the method of phase-separation mediated by the PAA-b-PAN-b-PAA tri-block copolymer. In the phase-separation procedure, the ionic block copolymer self-assembled on the surface of carbon nanofibers, and is used to adsorb NHVO. Thermal treatment at controlled temperatures under an NH : N atmosphere led to the formation of vanadium nitride nanoparticles that are distributed uniformly on the nanofiber surface. By changing the PAN to PAA-b-PAN-b-PAA ratio in the casting solution, a maximum specific capacitance of 240.5 F g is achieved at the current density of 0.5 A g with good rate capability at a capacitance retention of 72.1% at 5.0 A g in an aqueous electrolyte of 6 mol L KOH within the potential range of -1.10 to 0 V (rN/A = 1.5/1.0). Moreover, an asymmetric supercapacitor is assembled by using the hierarchical porous carbon fiber@vanadium nitride as the negative electrode and Ni(OH) as the positive electrode. Remarkably, at the power density of 400 W kg, the supercapacitor device delivers a better energy density of 39.3 W h kg. It also shows excellent electrochemical stability, and thus might be used as a promising energy-storage device.
在本研究中，采用由PAA-b-PAN-b-PAA三嵌段共聚物介导的相分离方法，制备了一种基于分级多孔碳纤维@氮化钒纳米颗粒的超级电容器混合电极材料。在相分离过程中，离子型嵌段共聚物在碳纳米纤维表面自组装，并用于吸附NHVO。在NH : N气氛下于可控温度进行热处理，导致在纳米纤维表面均匀分布形成氮化钒纳米颗粒。通过改变浇铸溶液中PAN与PAA-b-PAN-b-PAA的比例，在0.5 A g的电流密度下实现了240.5 F g的最大比电容，在6 mol L KOH的水性电解质中，在-1.10至0 V的电位范围内，在5.0 A g的电流密度下具有良好的倍率性能，电容保持率为72.1%（rN/A = 1.5/1.0）。此外，以分级多孔碳纤维@氮化钒为负极、Ni(OH)为正极组装了不对称超级电容器。值得注意的是，在400 W kg的功率密度下，该超级电容器器件具有39.3 W h kg的较好能量密度。它还表现出优异的电化学稳定性，因此可能用作有前景的储能器件。
