Co-Fe普鲁士蓝/多壁碳纳米管复合材料的超电容性能

Supercapacitive performance of Co-Fe Prussian blue analogue/multi-walled carbon nanotube composites

Co-Fe普鲁士蓝(CoPBA)是目前被广泛研究的超级电容器正极材料,其比电容高循环性能好,但低导电性和较差的倍率性能限制了其在超级电容器中的应用。为了提高CoPBA的导电性和电化学性能,本文以Co-glycerate为前驱体,采用牺牲模板法制备了Co-Fe普鲁士蓝/多壁碳纳米管(CoPBA/MWCNT)复合材料,利用XRD、SEM和FTIR等对复合材料的结构和形貌进行表征,使用电化学工作站在三电极体系和非对称超级电容器中测定了复合材料的电化学性能。实验结果表明:采用牺牲模板法成功合成出形貌较好的球状复合材料,以中性溶液Na_(2)SO_(4)为电解液,测得在1 A/g的电流密度下复合材料的质量比电容达到391.5 F/g。在10 A/g的高电流密度下比电容达到312.6 F/g,为1 A/g时的79.8%。利用软件模拟得出电荷转移电阻由3.9Ω降低到1.1Ω。以CoPBA/MWCNT为正极,以活性炭为负极制成非对称电容器,在功率密度为1092 W/kg时能量密度可达39.5 Wh/kg,5000次循环后容量保持率为85.2%。采用牺牲模板法制备的CoPBA/MWCNT,其电容、导电性和倍率性能均有提高,并具有较高的实际应用价值。

Co-Fe Prussian blue analogue (CoPBA) as a promising cathode material for supercapacitors has attracted much attention due to its high specific capacitance and good cycle performance. However,the disadvantages of poor conductivity and rate performance limit its use in supercapacitors. In order to improve the conductivity and electrochemical performance of CoPBA, using Co-glycerate as a precursor, a CoPBA/multi-walled carbon nanotube (CoPBA/MWCNT) composite material was fabricated by sacrificial templates. The structure and morphology of the composite were characterized by XRD, SEM,and FTIR. The electrochemical performance of the composite was measured in three-electrode system and asymmetric supercapacitors based on electrochemical workstation. Results showed that spherical composites with good morphology were successfully synthesized by sacrificial templates.In neutral solution Na_(2)SO_(4), the specific mass capacitance of the composite reached 391.5 F/g at a current density of 1 A/g. At a high current density of 10 A/g, the specific capacitance reached 312.6 F/g, which was 79.8% of that of 1 A/g current density.The charge transfer resistance of the composite material was reduced from 3.9 Ω to 1.1 Ω in simulation. Asymmetric supercapacitors were fabricated with CoPBA/MWCNT as the positive electrode and activated carbon(AC) as the negative electrode. When the power density was 1 092 W/kg, the energy density reached 39.5 Wh/kg,and the capacity retention rate was 85.2% after 5 000 cycles. Therefore, the CoPBA/MWCNT fabricated by sacrificial templates has improved capacitive, conductivity, and rate performance,and has a wide range of practical applications.