Spatial Distribution Control on the Energy Storage Performance of PANI@PVA@ACNT-Based Flexible Solid-State Supercapacitors

Abstract

In this work, a redox and an electrochemical polymerization method were carried out separately to produce the composite PANI@PVA@ACNT-based flexible solid-state supercapacitor (FSC) device with symmetrical "sandwich structure". Interestingly different polymerization methods result in different spatial structures, which lead to significant difference in the ion transport behaviors and energy storage mechanisms. The redox-polymerized aniline (R-PANI) provides a 3D polyaniline network in the gel system which exhibits a diffusion-controlled energy storage mechanism. While the electrochemical-polymerized aniline (E-PANI) is found to form a PANI nanoparticles attached-CNTs structure which shows a more typical pseudocapacitive behavior and better rate performance. The maximum specific capacitance of the E-PANI@PVA@ACNT and R-PANI@PVA@ACNT device reached as high as 896 mF•cm −3 (206 mF•cm −2 ) and 667 mF•cm −3 (200 mF•cm −2 ) respectively, which is much better than the prepolymerized PANI@ACNT samples (216 mF•cm −3 ). In addition, the composite devices based on highly densified carbon nanotube arrays (DACNTs) were found to have a superior electrochemical performance. The maximum specific capacitance of the E-PANI@PVA@DACNT and R-PANI@PVA@DACNT device reached as high as 1.95 F•cm −3 (432 mF•cm −2 ) and 2.91 F•cm −3 (873 mF•cm −2 ), respectively. The highest energy density was measured to be 0.389 mW•h•cm −3 (0.09 mW•h•cm −2 ) for E-PANI@PVA@DACNT and 0.572 mW•h•cm −3 (0.17 mW•h•cm −2 ) for R-PANI@PVA@DACNT with high power density of 11.2 mW•cm −3 (2.58 mW•cm −2 ) and 74.4 mW•cm −3 (22.3 mW•cm −2 ), respectively. Besides, the long-term cyclic stability and excellent rate performance of such devices were also achieved. Our approach well overcomes the general obstacle that the hydrogel electrolyte is likely blocked by the carbon-based electrode materials in the FSC system. In addition, our findings reveal that the relationship between the spatial distribution and energy storage mechanisms of mixed-type supercapacitor devices thus helps the design of redox-enhanced FSC devices with excellent performances.

Nanostructured Polyaniline/Graphene/Fe2O3 Composites Hydrogel as a High-Performance Flexible Supercapacitor Electrode Material

“…Flexible supercapacitors (FSCs) are new emerging energy storage devices having great mechanical compliance and high power density, making them suitable as power back-ups for next-generation flexible electronics because they could work under bending and even twisting states. , Depending upon the storage mechanism, supercapacitors (SCs) can be categorized as pseudocapacitors , and electrochemical double-layer capacitors (EDLCs) . Carbon-based materials such as carbon fibers, carbon nanotubes, activated carbon, and graphene (GN) , are consider as best electrode materials for EDLCs,whereas conjugated polymers (CPs) and transition metal oxides (TMOs) and phosphides have been used as electrodes in Faradaic-capacitors/pseudocapacitors because of their reversible redox processes and high surface area. It is recognized that conducting polymers are optimal electrode materials for stretchable energy storage devices …”

“…11,12 Depending upon the storage mechanism, supercapacitors (SCs) can be categorized as pseudocapacitors 13,14 and electrochemical double-layer capacitors (EDLCs). 15 Carbon-based materials such as carbon fibers, 16 carbon nanotubes, 17 activated carbon, 18 and graphene (GN) 19,20 are consider as best electrode materials for EDLCs,whereas conjugated polymers (CPs) 21 and transition metal oxides (TMOs) 22 and phosphides 23 have been used as electrodes in Faradaiccapacitors/pseudocapacitors because of their reversible redox processes and high surface area. It is recognized that conducting polymers are optimal electrode materials for stretchable energy storage devices.…”

Facile Synthesis of CoSe/Co3O4-CNTs/NF Composite Electrode for High-Performance Asymmetric Supercapacitor

“…ASCs especially usually combine advantages of the two different types of electrodes, which can provide a high capacitance and a long cycle life [ 4 ]. As a main component of SCs, various electro-active materials have been explored, such as carbonaceous materials (carbon nanotubes [ 5 , 6 , 7 ] (CNTs), graphene [ 8 , 9 ] and active carbon [ 10 ]), transition metal-based materials (RuO 2 [ 11 ], MnO 2 [ 12 ], NiO [ 13 ], Co 3 O 4 [ 14 ]), sulfides [ 15 ], metal selenides [ 16 ] and conducting polymers (PANI [ 17 ], PPy [ 18 ], PEDOT [ 19 ]).…”

Enhanced Electrochemical Performance of a Hybrid Supercapacitive Material Based on Ternary Doped Polyaniline/Activated Carbon Composite

“…Ye et al synthesized a PANI/PVA/CNTbased flexible supercapacitor with a specific capacitance of 896 mF/cm 3 along with good cyclic stability and excellent rate performance. 43 Mn-ion-doped Ni−Co-layered double hydroxide nanosheet-coated polyaniline-derived carbon was fabricated by Cao et al This showed a higher specific capacitance of 1282.06 C/g and 82.66% capacity retention following 10 000 cycles, exhibiting a high energy density of 78.9 Wh/kg at a power density of 1.55 kW/kg. 44 Hsu et al 45 developed a nanocellulose-based polyaniline-reduced graphene oxide sandwich-like supercapacitor electrode with high flexibility, mechanical strength, and conductivity.…”

“…Nowadays, great endeavors have gone into the most felicitous choice of materials for developing a hybrid supercapacitor. Ye et al synthesized a PANI/PVA/CNT-based flexible supercapacitor with a specific capacitance of 896 mF/cm 3 along with good cyclic stability and excellent rate performance . Mn-ion-doped Ni–Co-layered double hydroxide nanosheet-coated polyaniline-derived carbon was fabricated by Cao et al This showed a higher specific capacitance of 1282.06 C/g and 82.66% capacity retention following 10 000 cycles, exhibiting a high energy density of 78.9 Wh/kg at a power density of 1.55 kW/kg .…”