Daraghmeh Allan, Hussain Shahzad, Saadeddin Iyad, Servera Llorenç, Xuriguera Elena, Cornet Albert, Cirera Albert
MIND, Engineering Department: Electronics, Universitat de Barcelona, Marti i Franquès 1, 08028, Barcelona, Spain.
Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Joan XXIII S/N, 08028, Barcelona, Spain.
Nanoscale Res Lett. 2017 Dec 29;12(1):639. doi: 10.1186/s11671-017-2415-z.
Symmetric supercapacitors are fabricated by carbon nanofibers (CNF) and activated carbon (AC) using similar proportions of 7 wt% polyvinylidene fluoride (PVDF) polymer binder in an aqueous electrolyte. In this study, a comparison of porous texture and electrochemical performances between CNFs and AC based supercapacitors was carried out. Electrodes were assembled in the cell without a current collector. The prepared electrodes of CNFs and AC present Brunauer-Emmett-Teller (BET) surface area of 83 and 1042 m/g, respectively. The dominant pore structure for CNFs is mesoporous while for AC is micropore. The results showed that AC provided higher specific capacitance retention up to very fast scan rate of 500 mV/s. AC carbon had a specific capacitance of 334 F/g, and CNFs had 52 F/g at scan rate 5 mV/s in aqueous solution. Also, the results indicate the superior conductivity of CNFs in contrast to AC counterparts. The measured equivalent series resistance (ESR) showed a very small value for CNFs (0.28 Ω) in comparison to AC that has an ESR resistance of (3.72 Ω). Moreover, CNF delivered higher specific power (1860 W/kg) than that for AC (450 W/kg). On the other hand, AC gave higher specific energy (18.1 Wh/kg) than that for CNFs (2 Wh/kg).This indicates that the AC is good for energy applications. Whereas, CNF is good for power application. Indeed, the higher surface area will lead to higher specific capacitance and hence higher energy density for AC. For CNF, lower ESR is responsible for having higher power density.Both CNF and AC supercapacitor exhibit an excellent charge-discharge stability up to 2500 cycles.
对称超级电容器由碳纳米纤维（CNF）和活性炭（AC）制成，在水性电解质中使用7 wt%的聚偏二氟乙烯（PVDF）聚合物粘合剂，比例相似。在本研究中，对基于CNF和AC的超级电容器的多孔结构和电化学性能进行了比较。电极在没有集流体的情况下组装在电池中。制备的CNF和AC电极的布鲁诺尔-埃米特-泰勒（BET）表面积分别为83和1042 m²/g。CNF的主要孔结构是中孔，而AC的主要孔结构是微孔。结果表明，在高达500 mV/s的非常快的扫描速率下，AC具有更高的比电容保持率。在水溶液中，扫描速率为5 mV/s时，AC碳的比电容为334 F/g，CNF的比电容为52 F/g。此外，结果表明，与AC相比，CNF具有更高的导电性。测量的等效串联电阻（ESR）显示，CNF的值非常小（0.28 Ω），而AC的ESR电阻为（3.72 Ω）。此外，CNF的比功率（1860 W/kg）高于AC（450 W/kg）。另一方面，AC的比能量（18.1 Wh/kg）高于CNF（2 Wh/kg）。这表明AC适用于能量应用。而CNF适用于功率应用。实际上，较高的表面积将导致AC具有更高的比电容，从而具有更高的能量密度。对于CNF，较低的ESR导致其具有更高的功率密度。CNF和AC超级电容器在高达2500次循环时均表现出优异的充放电稳定性。
