Improved performance of asymmetric fiber-based micro-supercapacitors using carbon nanoparticles for flexible energy storage

Abstract

Recently, a high-performance energy storage device is urgently needed due to the rapid development of miniaturized, portable and wearable electronic equipment.However, most of the single-cell energy storage devices are suffered from relatively low operating voltage. In this work, we present a novel fiber-based micro-asymmetric supercapacitor (ASC) with high performance and good integrated ability. Carbon nanoparticles coated on carbon fiber (CF@CNPs) is chosen as the substrate owing to its notable features such as high porosity, high flexibility, lightweight, simple processing and ease of integration. The manganese oxide nanosheet grown on CF@CNPs and functionalized CF@CNPs are employed as the positive and negative electrode of the micro-ASC respectively. The as-prepared ASC device can operate at 1.8 V and exhibit a high volumetric energy density of 2.1 mWh cm -3 , which is comparable to that of a thin-film Li-battery. Furthermore, the micro-ASC can achieve a very high capacitance retention of about 82.7 % when the charge and discharge current density is changed from 0.25 A cm -3 to 6.3 A cm -3 , demonstrating an excellent rate capability of the ASC. The ASC also shows good cycling stability and has great potential to be integrated with energy harvesting devices to realize high-efficient self-powered systems.

Materials Design and System Construction for Conventional and New‐Concept Supercapacitors

“…In addition, mesoporous carbon particles and carbon microfiber are bundled onto the alignment of CNTs to produce fiber electrodes . The presence of mesoporous carbon favors a rapid charge separation and transport and accessible to the electrolyte solution resulted from the high specific surface area and pore structure.…”

Realization of high performance flexible wire supercapacitors based on 3-dimensional NiCo2O4/Ni fibers

“…S9c †) of 3D-NCO/Ni-3, 3D-NCO/Ni-2 and 3D-NCO/Ni-1 were 336, 300, and 233 F g À1 , respectively, with a capacitance retention of 95.5, 97.5 and 93.1% as the current was increased from 2.5 to 20 mA. The achieved specic capacitance (C v , C a , and C g ) was signicantly higher than that of previously reported ber electrodes, such as a MnO 2 / graphene/carbon bre and graphene hydrogel wrapped copper wire (13.7 F cm À3 , and 73 F cm À3 at 0.5 mA cm À2 ), 29 a MWCNTs/ CMF (14.1 F cm À3 at 5 mV s À1 ), 30 Ni(OH) 2 nanowire bre and ordered mesoporous carbon bre electrode (270 F g À1 and 76.7 F g À1 at 0.5 mA), 31 MnO 2 /carbon nanoparticles/carbon ber and functionalize carbon nanoparticles/carbon ber (27.5 F cm À3 and 22.5 F cm À3 at 5 mV s À1 ), 32 hydrogenated single crystal ZnO@amorphous ZnO-doped MnO 2 core-shell nanocable (138.7 mF cm À2 at 1 mA cm À2 ), 33 TiO 2 @C (31.3 mF cm À2 at 10 mV s À1 ) 34 and graphene/polypyrrole (G/PPy) composite bers (115 mF cm À2 at 0.2 mA cm À2 ). 35 The excellent electrochemical performance of the conductive additive and binder-free 3D-NiCo 2 O 4 /3D-Ni electrode can be attributed to the following reasons.…”

Hierarchical core–shell heterostructure of porous carbon nanofiber@ZnCo2O4nanoneedle arrays: advanced binder-free electrodes for all-solid-state supercapacitors

“…Thus, in order to form a reasonable specic voltage and capacitance rating for some practical microelectronic applications, supercapacitors need to be connected together in series or parallel combinations. 61,62 Fig. 8a exhibits the galvanostatic charge/discharge curves of a single device and two devices connected in series.…”