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Three-Dimensional Reduced Graphene Oxide/Poly(3,4-Ethylenedioxythiophene) Composite Open Network Architectures for Microsupercapacitors

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Abstract

The three-dimensional (3D) porous nanostructures have shown attractive promise for flexible microsupercapacitors due to their merits of more exposed electrochemical active sites, higher ion diffusion coefficient, and lower charge-transfer resistance. Herein, a highly opened 3D network of reduced graphene oxide/poly(3,4-ethylenedioxythiophene) (rGO/PEDOT) was constructed through the laser-assisted treatment and in situ vapor phase polymerization methods, which can be employed with gel electrolyte to prepare flexible microsupercapacitors, without conductive additives, polymer binder, separator, or complex processing. These porous open network structures endow the obtained microsupercapacitors with a maximum specific capacitance (35.12 F cm−3 at 80 mA cm−3), the corresponding energy density up to 4.876 mWh cm−3, remarkable cycling stability (with only about 9.8% loss after 4000 cycles), and excellent coulombic efficiency, which are comparable with most previous reported rGO-based microsupercapacitors. Additionally, the microsupercapacitors connected in series/parallel have been conveniently fabricated, followed by being integrated with solar cells as efficient energy harvesting and storage systems. Moreover, the working voltage or energy density of microsupercapacitors array can be easily tailored according to the practical requirements and this work provides a promising approach to prepare high-performance flexible micro-energy device applied in the wearable electronics accordingly.

Introduction

These dramatically pervasive smart microelectronic devices such as wireless sensor networks for on-line monitoring, biomedical implants for human health care, and real-time tracking chips, have led to the growing demands of lightweight, flexible, low cost, and highly efficient micro-scale energy storage devices [1,2,3]. Currently, commercially available thin-film and 3D micro-batteries, as the major micro-power sources, often suffer from poor rate performance, abrupt failure, and safety concerns. In comparison, interdigital microsupercapacitors (MSCs) are the dominant candidates in self-powered microelectronic devices because of their competitive power density, excellent safety, and superior rate capability, as well as long operational lifespan [4,5,6]. As one of the common configurations, the two-dimensional (2D) interdigital MSCs are widely employed due to their greatly reduced thickness and relatively high-power supply compared with a commercial supercapacitor. In general, the 2D interdigital MSCs need thicker microelectrodes to meet energy demand in a given footprint, whereas the thick microelectrodes may offer poor accessibility to electrolyte, insufficient charge transport, and increasing electron/ion diffusion distances, resulting in degrading the capacity and rate performance [1]. Thus, it is still challenging to increase their energy/power densities without compromising other electrochemical characteristics simultaneously in a limited footprint area.

Notably, the 3D opened network architecture has attracted great attention, owing to the merits of higher specific surface area, rapid ion transport, and buffer volume change during GCD cycle tests [7]. Until now, majority of approaches have been applied to synthesize 3D opened network microelectrodes including colloidal template [8, 9], hard template [10, 11], hydrothermal method [7, 12], and deposition on 3D substrates [4, 13, 14]. However, these conventional fabrication techniques often need the toxic agents, harsh synthetic conditions, or complex preparation technique, resulting in difficulties to obtain the cost-effective, large-scale, and environmentally friendly devices for commercial application. To overcome these obstacles, tremendous efforts have been devoted to exploring new strategies to manufacture 3D opened network MSCs efficiently. Impressively, the readily scalable and low-cost laser-assisted treatment [15,16,17], which can design the treating circuit at precise locations by software control to form the desired patterns without additional external wire, has attracted widespread attention to fabricate in-plane opened network MSCs. Additionally, the vapor phase polymerization (VPP) method involves the polymerization of precursor in the vapor phase onto the surface of oxidant [18], and it is readily tailored to prepare any desired patterns on varied substrates conveniently. More importantly, the VPP method is obvious superiority compared with chemical vapor deposition (CVD) [19], electrochemical deposition [20, 21], and in situ chemical polymerization [22], because it can get rid of the constraints of specialized vacuum equipment, electrolytic deposition device, or solvent processing.

As the key component for in-plane interdigital MSCs, microelectrode materials with the high surface areas, good hydrophilicity, and excellent ion intercalation behavior should be explored to improve their energy storage performance. Especially, rGO has aroused widespread attention due to its low-cost and abundant raw material (graphite), high electrical conductivity, and high surface area (2630 m2 g−1) [1]. However, the rGO-based MSCs generally release a relatively low specific capacitance, and the charges only accumulate at the interface between the electrode and electrolyte, resulting from the electrochemical double-layer capacitance energy storage mechanism [23]. In addition, conducting polymers such as PEDOT and their derivatives, which rely on fast and reversible faradaic redox reactions at the surface and/or in the bulk [24], have been intensively investigated as pseudo-capacitor electrodes because of their low toxicity, high conductivity, stable doped form, and low cost. Consequently, the rGO made by laser-assisted treatment and PEDOT via readily scalable VPP method are the optimal combination to fabricate opened network rGO/PEDOT microelectrodes.

Herein, we constitute the high-performance all-solid-state flexible microsupercapacitors based on interdigital rGO/PEDOT composite. Notably, the interconnected network rGO derived from graphene oxide (GO) by laser-assisted treatment is adopted as a conductive framework, ascribing to its merits of the tuning the surface morphology, controlling the desired pattern at precise locations, enhancing electrolyte wetting or diffusion kinetics. Then, the 3D open porous PEDOT prepared by VPP method can provide the accessibility to the electrolyte ions, shorter planar ionic diffusion path, and more electrochemical active sites. The in-plane interdigital MSCs employed these obtained rGO/PEDOT microelectrodes with PVA/H3PO4 gel electrolyte showed a maximum specific capacitance of 35.12 F cm−3, the energy density of 4.876 mWh cm−3 at 40 mW cm−3 under the current density of 80 mA cm−3, and outstanding cycling stability after 4000 cycles. Additionally, the MSCs connected in series/parallel had been constructed to power the red light-emitting diode (LED) light about 100 s when fully charged. Therefore, this work provides a facile way to prepare coplanar interdigital MSCs as micro-storage sources for next-generation highly integrated portable microelectronic devices where high capacity per limited footprint is critical.

Experimental Methods

Materials

The 3,4-ethylenedioxythiophene (EDOT) monomers were provided by Bayer AG. Iron (III) p-toluenesulfonate (Fe(PTS)3) and polyvinyl alcohol (PVA) powders were bought from Sigma-Aldrich. The GO nanosheets were purchased from Pioneer Nanomaterials Technology. Polyethylene terephthalate (PET) substrate, sodium dodecyl benzenesulfonate (NaDBS), phosphoric acid (H3PO4), acetone, ethanol, and other reagents were provided by Kelon Chemical Industry Co., Ltd. All the chemical reagents were used without further treatment. The program controlled the 788 nm infrared laser (maximum power output = 5 mW) inside a consumer-grade LightScribe optical drive unit by periodically pulsing an objective lens assembly, and the desired pattern can be prepared rapidly at precise locations. All the experiments were performed under ambient conditions.

Synthesis of 3D Opened Network rGO/PEDOT Interdigital Electrodes

Figure 1a shows a schematic illustration of the fabrication of rGO/PEDOT interdigital electrodes. In a typical procedure, a flexible polyethylene terephthalate (PET) substrate was cut into a square piece (2 cm × 2 cm) and was washed with ethanol, acetone, and deionized water several times, respectively. The GO was synthesized using a modified Hummer’s method [25], and the homogeneous 2% GO dispersion in deionized water was prepared by ultrasonic dispersion [26]. Then, the GO film was deposited on the PET substrate and allowed to dry about 24 h under ambient conditions. Subsequently, the GO-coated PET was put into the consumer-grade LightScribe optical drive unit for laser patterning, and 500 μs exposure duration of each voxel was adopted using the 788 nm infrared laser (power output about 100 mW). After setting the desired patterns into a computerized commercial drive, the conductive rGO interdigital electrodes were prepared rapidly at precise locations by periodically pulsing on the insulating GO film about 30 min, as our previously reported [21, 27].

Fig. 1
figure1

a Schematic illustration of the fabrication of rGO/PEDOT interdigitated electrodes. b The polymerization mechanism of PEDOT

Prior to fabricating the porous PEDOT by VPP, the as-prepared rGO sample was treated by 0.5 mg mL−1 NaDBS aqueous solution as the surfactant for 20 min and then baked at 80 °C about 5 min. The molar ratio 1:1 of Fe(PTS)3 to isopropanol was prepared as oxidant solution by magnetic stirring, which was then selectively deposited on the as-treated rGO interdigital electrodes with a mask by the spraying method. Subsequently, the obtained sample was positioned at the center of a small chamber containing 100 μL EDOT monomers, and the whole device was heated in the vacuum desiccator. The polymerization mechanism of PEDOT by VPP was shown in Fig. 1b. After applying the above samples exposed in the EDOT vapor at 30 °C, 50 °C, 80 °C, and 100 °C for 30 min, these highly 3D opened network rGO/PEDOT microelectrodes were fabricated, noting as rGO/PEDOT-30, rGO/PEDOT-50, rGO/PEDOT-80, and rGO/PEDOT-100, respectively. Additionally, the pristine rGO interdigital electrodes were also prepared as a comparison.

Assembly of Highly Opened Network rGO/PEDOT-Based Flexible Interdigital MSCs

Typically, the PVA powder (1 g) was dissolved into deionized water (10 mL) at 90 °C for 2 h under vigorous stirring, then the H3PO4 (2 mL) was gradually added under slowly stirring at ambient temperature until forming a transparently jelly-like solution, and the PVA/H3PO4 gel electrolyte was successfully prepared. In addition, a metal coat was firstly covered on the surface of electrodes by sputtering as current collector, and the PVA/H3PO4 gel electrolyte was drop by drop covered onto the rGO/PEDOT interdigital electrodes. Subsequently, the device was soaked at room temperature for 10 h to ensure completely wet and evaporation of any excess water. Finally, the all-solid-state MSCs were successfully assembled.

Characterization and Measurement

The morphologies, microstructural, and component characterizations were performed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, the electrochemical properties (cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) of flexible planar MSCs were examined by two-electrode cell on a CHI660D electrochemical workstation (Chen Hua, Shanghai) under ambient temperature.

The volumetric specific capacitances Cv (F cm−3), energy densities W (Wh cm−3), and power densities P (W cm−3) were calculated from the GCD curves at different current densities using the following Eqs. (1)–(3): [13, 17, 24].

$$ {C}_{\mathrm{v}}=\frac{I\times \Delta t}{V\times \Delta E} $$
(1)
$$ W=\frac{C_{\mathrm{v}}\times {\Delta E}^2}{2\times 3600} $$
(2)
$$ P=\frac{W}{\Delta t} $$
(3)

where I is the discharge current (A); Δt is the discharge time (s); V is the stack volume (cm3) which includes the combined volume of the active material, current collector, and the gap between the electrodes; and ΔE is the potential window (V).

Results and Discussion

Morphology and Structure of the GO, rGO, and rGO/PEDOT Electrode Materials

The morphologies of the GO, rGO, and rGO/PEDOT were investigated by SEM shown in Fig. 2. Firstly, the richly 3D wrinkle-like rGO (Fig. 2b) derived from GO sheets (Fig. 2a) by the laser treating process can provide abundant charge carrier sites and allow ions to readily access or penetrate into their internal surfaces between the electrode and electrolyte. Importantly, these synergistic interactions of rGO and PEDOT networks are beneficial for shortening the diffusion distance and facilitating ion transport to achieve excellent energy storage properties [28]. Furthermore, the top view and the cross-section images of the four rGO/PEDOT samples polymerized at 30 °C, 50 °C, 80 °C, or 100 °C by VPP reveal various porous configurations (Fig. 2c–h). Additionally, compared with other three rGO/PEDOT samples, the rGO/PEDOT-50 (Fig. 2d) shows the homogeneous porous network structure, which is beneficial to improve the specific surface area and abundant conductive path. This may be owing to the appropriately slow evaporation of the side product acid and low-film growth rate at 50 °C, which are beneficial to endow homogeneous porous network during the polymerization process. Moreover, the higher polymerization temperatures (such as 80 °C, 100 °C) may tend to greater heterogeneous nucleation to form the dense flat morphology because of the higher EDOT vapor concentration and faster reaction rates, while the polymerization temperatures at 30 °C is too low to inadequate polyreaction [29, 30].

Fig. 2
figure2

The typical SEM images of top view for a GO, b rGO, c rGO/PEDOT-30, d rGO/PEDOT-50, e rGO/PEDOT-80, and f rGO/PEDOT-100. The cross-section images g and h of rGO/PEDOT-50

The FTIR and Raman measurements of GO, rGO, and PEDOT were also performed to characterize the changes of chemical compositions in Fig. 3. The typical characteristic peaks of GO (Fig. 3a) exhibit the C=O (1724 cm−1), C=C (1618 cm−1), C–OH (1410 cm−1), C–O (1046 cm−1), and C–O–C (848 cm−1). After laser-assisted treatment, all the absorption peaks of oxygen-containing functional groups were nearly removed, indicating the successful preparation of rGO (Fig. 3a). Additionally, these characteristic peaks of PEDOT, such as the asymmetric C=C stretching peak (1630, 1513 cm−1) [31], the C–C stretching mode (1350 cm−1), C–O–C deformation peak (1190, 1085 cm−1), symmetric C–S–C deformation peak (978, 920, 830, and 688 cm−1) [32] could be observed in Fig. 3b, further confirming the existence of PEDOT. Therefore, these FTIR spectra confirm the successful preparation of rGO/PEDOT composite through the laser reduction and VPP methods.

Fig. 3
figure3

FTIR spectra of a GO, rGO, and b PEDOT. c Raman spectra of GO, rGO, and PEDOT

Figure 3c shows the Raman spectra of GO, rGO, and PEDOT. The D band is triggered by defects in the hexagonal carton materials, and the G band arose from the graphitic carbon (E2g mode). Furthermore, the intensity ratio of the D and G bands (ID/IG) is widely used to evaluate the disordered and ordered domains of graphene [27]. Obviously, the D (1359 cm−1) and G (1595 cm−1) bands of GO and rGO are both present in Fig. 3c, and the ID/IG of GO and rGO are 1.02 and 0.92, respectively. The ID/IG of rGO is lower comparing with GO, signifying the less defects of rGO after laser-induced treatment. More importantly, the prominent 2D peak (2687 cm−1) appears in the Raman spectra of rGO, further verifying the presence of few layer graphene [33]. Additionally, the 1548 and 1487 cm−1 peaks (Cα = Cβ), 1433 cm−1 peak (Cα = Cβ (−O)), 1365 cm−1 peak (CαCβ), 1258 cm−1 peak (CαCα), 1130 cm−1 peak (C–O–C), 988 cm−1 and 854 cm−1 peaks (C–S–C), and 442 cm−1 peak (S–O) are clearly observed in Raman spectra of PEDOT, which are in good accordance with the reported literature [34]. The above analyses evidently demonstrate the successful preparation of rGO and PEDOT.

The XPS spectrum analysis of rGO/PEDOT, GO, and rGO were performed to monitor the oxygen functionalities (Fig. 4). The C1s spectrum of GO (Fig. 4a) and rGO (Fig. 4b) are resolved into multiple peaks of C–C (284.8 eV), C=O (287.3 eV), C–O (286.2 eV), and O–C=O (288.5 eV). In contrast to GO, the significant removal of oxygen-containing functional groups (C=O and O–C=O) and an overall increase in the C–C sp2 carbon peak of rGO point to an efficient deoxygenation process as well as restoration π-conjugated structure, resulting in a higher electrical conductivity after laser treating, these results also agree with the previous reports [35, 36]. The presence of C–S bonds (285.3 eV) in Fig. 4c further confirms the successful synthesis of PEDOT on the rGO. Moreover, Fig. 4d shows the S2p peak of rGO/PEDOT cracked into S2p3/2 (162.6 eV) and S2p1/2 (163.8 eV) doublets with a corresponding 1.2 eV separation, originating from the S atom bonded onto the thiophene ring structure in the chains of PEDOT [19, 32, 37].

Fig. 4
figure4

The survey XPS spectrum for C1s peaks of a GO, b rGO, and c rGO/PEDOT and d S2p peak of rGO/PEDOT

Electrochemical Behavior of the Flexible MSCs with Opened Network rGO/PEDOT

The as-prepared porous rGO/PEDOT electrodes can be conveniently assembled into the flexible planar MSCs with PVA/H3PO4 gel electrolyte, without any conductive additives or binders as well as obtaining simplified and lightweight energy storage devices. In order to evaluate the performance of rGO/PEDOT-based MSCs, their electrochemical properties (Fig. 5) were subsequently investigated via CV, GCD, and EIS measurements using a two-electrode configuration. Figure 5a displays the representative CV plots of rGO/PEDOT-30, rGO/PEDOT-50, rGO/PEDOT-80, rGO/PEDOT-100, and pristine rGO-based MSCs at 20 mV s−1. Among them, the CV curve of rGO/PEDOT-50-based MSCs shows a largest quasi-rectangular area, indicating its ideal capacitive behavior. Also, the comparison of GCD curves at 80 mA cm−3 was presented in Fig. 5b, which show almost triangular shapes and the potential is nearly linear to charge/discharge time [21]. Impressively, the rGO/PEDOT-50-based MSCs endure the longest discharge time than those for other samples. Additionally, the Nyquist plot of rGO/PEDOT-50-based MSCs (Fig. 5c) shows a nearly vertical profile in the low-frequency region and the smaller inner impedance compared with other samples. Furthermore, the specific capacitances calculated according to the Eqs. (1)–(3) versus discharge current density are shown in Fig. 5d. The corresponding specific capacitance of rGO/PEDOT-50-based MSCs was revealed about 35.12 F cm−3 at 80 mA cm−3, the specific capacitance displays a gradual drop with increasing the current density, but it still can deliver a relatively high capacity of 31.04 F cm−3 at 400 mA cm−3 compared to the other four samples, further proving its excellent rate capability.

Fig. 5
figure5

The compared electrochemical properties of various rGO/PEDOT composites with different reaction temperature-based MSCs: a CV curves at 20 mV s−1 and b GCD curves at 80 mA cm−3. c Nyquist plots from the EIS analysis obtained from 0.01 Hz to 100 kHz. d Specific capacitance versus different current densities

To further explore the feasibility of rGO/PEDOT-50-based MSCs, their electrochemical performances were evaluated in Fig. 6. The CV curves retain nearly rectangular shapes with the increasing scan rates from 10 to 100 mV s−1 (Fig. 6a), which practically stems from the reversible surface redox reactions of PEDOT and surface electroadsorption of rGO, resulting in the fast charge/discharge rate and the ideal capacitive behavior [38]. Additionally, Fig. 6b shows GCD curves at different current densities under the potential window of 0~1 V, and the nonlinear slopes and triangle shape particularly at lower current densities corroborate the contribution of the pseudo-capacitance from PEDOT, which agrees well with recent reports [39, 40]. Furthermore, the flexibility tests of the planar rGO/PEDOT-50-based MSCs were performed at different angles (Fig. 6c), and the CV curves at 10 mV s−1 were almost overlapped under bending with increasing bending angles from 0° up to 180°. Subsequently, the MSCs were bent at 180° for 1000 cycles by a linear motor, and the specific capacitance calculated from the charge/discharge curves retention of 96.8% was achieved after 1000 bending cycles (Fig. 6d). So our MSC devices possess excellent mechanical flexibility, which is mainly ascribed to the flexible PET substrate and the strong adhesion of the 3D highly porous structure with the substrate [41]. These results also confirm the excellent synergistic effect between the laser reduction rGO and VPP polymerized PEDOT. For a micro-device, the energy density and power density are the two critical factors to evaluate its practicality. Therefore, the Ragone plots of as-prepared MSCs and comparison with some other previously reported MSCs are plotted in Fig. 6e. The flexible planar rGO/PEDOT-50-based MSCs deliver a maximum energy density of 4.876 mWh cm−3 at a power density of 40 mW cm−3, and with the evidence that still remains 4.422 mWh cm−3 at 200 mW cm−3. These obtained results are comparable or higher than other recent reported MSCs with PVA-based aqueous gel electrolyte such as Janus graphene film MSCs [42], rGO MSCs [28], MnOx/Au MSCs [43], Li thin-film battery [44], MWNT/carbon fiber MSC [45], rGO/SWNT@CMC MSC [46], carbon/MnO2 MSC [47], or laser-processed graphene MSC [48]. The cyclability tests and coulombic efficiency of rGO/PEDOT-50-based MSCs over 4000 charge/discharge cycles at a current density of 80 mA cm−3 are shown in Fig. 6f. It can be seen that the volumetric specific capacitances keep stable with the retention capacitance of 90.2% after 4000 cycles, and the coulombic efficiencies keep 97~99% during the whole cycles, demonstrating the excellent durability and reversibility of rGO/PEDOT-50-based MSCs.

Fig. 6
figure6

The electrochemical performances of rGO/PEDOT-50-based flexible all-solid-state MSCs: a CV curves at various scan rates; b GCD curves at different current densities; c CV curves obtained under different bending angles at 10 mV s−1; d Capacitance retention as a function of bending cycles at a current density of 80 mA cm−3; e Ragone plots of the device and some other reported MSCs, and f cyclability tests and coulombic efficiency over 4000 charge/discharge cycles at a current density of 80 mA cm−3

In general, the working voltage, electric current, or capacitances of a single MSC device are too low to meet the demands of miniaturized electronic devices [49]. Therefore, the rGO/PEDOT-50-based MSC array connected in series/parallel was fabricated (Fig. 7) via the cost-effective laser treatment and readily scalable VPP method. Figure 7a shows the moving path of the electrolyte ions along the planar surface of the MSC array integrated with miniaturized electronic devices. Figure 7b–d show a self-powered system integrated a flexible MSC array with solar cells, which is successfully proved by lighting a LED under the deformation state of MSC array. Figure 7e and f show the CV curves at 20 mV s−1 and GCD curves at 40 mA cm−3 of MSC array, respectively. And the optical images of the assembled MSC array were inserted in Fig. 7e. Especially, the voltage window of MSC array connected in 2P × 3S was expanded up to 3 V, three times higher than that of a single MSC (Fig. 7e), while the charge/discharge time is approximately double of a single device (Fig. 7f), which indicates that the MSC array roughly obeys the basic rules of series/parallel connections [17], and the energy densities of MSC array connected in 2P × 3S were increased by six times comparing to a single MSC. These superior electrochemical performances of rGO/PEDOT-based MSC array owes much to the following possible factors: (1) the interdigitated structures enable the electrolyte ions a higher ion diffusion coefficient as well as shorten planar ionic diffusion path, resulting in further improving their rate capability [41]. (2) The reaction temperature was optimized and the PEDOT direct-growth on rGO at 50 °C by VPP can supply a strong adhesion between their interfacial contact, thus endowing a good electron pathway and enhancing electrochemical durability. (3) The synergistic effect of 3D highly porous structure PEDOT and silk-like rGO (shown in Fig. 2) leads to a large surface area, massive exposed electrochemical reaction active sites, the accessibility to the electrolyte ions, and lowers charge-transfer resistance [50, 51]. Benefiting from the above advantages, the rGO/PEDOT-based MSCs exhibit excellent energy storage characteristics, making them promising micro-energy devices in miniaturized electronic applications.

Fig. 7
figure7

Fabrication of rGO/PEDOT-50-based MSC array as micro-energy storage devices. a Schematic of showing the working principle of MSC array integrated with miniaturized electronic devices. b~d Integration of a flexible MSC array with solar cells for lighting a LED. e The CV curves at 20 mV s−1 and f GCD curves at 40 mA cm−3 of MSC array connected in series (2 cells in series, 2S), in parallel (2 cells in parallel, 2P), and in a combination of series and parallel (2 parallel × 3 series, 2P × 3S). The optical images of MSC array insert in e

Conclusions

In summary, we provide a feasible strategy to conveniently prepare the MSC array with 3D opened network of rGO/PEDOT interdigital electrodes using the laser treating and VPP methods. Interestingly, the required working potential or electric current in most practical applications could be easily tailored by connecting in series/parallel without additional voltage balance management. The obtained rGO/PEDOT-50-based planar interdigital MSCs deliver the high specific capacitance of 35.12 F cm−3 (the corresponding energy density of 4.876 mWh cm−3) at 80 mA cm−3, stable cycling stability (90.2% for 4000 cycles), superior rate capability, excellent coulombic efficiency (keep 97~99% during the whole cycle), and good flexibility under different bending angles. Considering the convenient fabrication, high performances, excellent size compatibility, and flexibility, the rGO/PEDOT-based MSC array is particularly a promising candidate for the next-generation high-performance flexible micro-energy sources integrated with microelectronic devices.

Availability of Data and Materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Abbreviations

2D:

Two-dimensional

3D:

Three-dimensional

CV:

Cyclic voltammetry

CVD:

Chemical vapor deposition

EIS:

Electrochemical impedance spectroscopy

Fe (PTS)3 :

iron (III) p-toluenesulfonate

FTIR:

Fourier transform infrared spectroscopy

GCD:

Galvanostatic charge/discharge

LED:

Light-emitting diode

MSCs:

Microsupercapacitors

PET:

Polyethylene terephthalate

PVA:

Polyvinyl alcohol

rGO/PEDOT:

Reduced graphene oxide/poly(3,4-ethylenedioxythiophene)

SEM:

Scanning electron microscope

VPP:

Vapor phase polymerization

XPS:

X-ray photoelectron spectroscopy

References

  1. 1.

    Liu ZY, Wu ZS, Yang S, Dong R, Feng X, Müllen K (2016) Ultraflexible in-plane micro-supercapacitors by direct printing of solution-processable electrochemically exfoliated graphene. Adv Mater 28(11):2217–2222

  2. 2.

    Hu HB, Hua T (2017) An easily manipulated protocol for patterning of MXenes on paper for planar micro-supercapacitors. J Mater Chem A 5(37):19639–19648

  3. 3.

    Chao L, Shan C, Tian ZN, Song YZ, Yu LH, Chen L, Shao YL, Jie L, Zou GF, Rümmeli MH, Dou SX, Sun JY, Liu ZF (2019) Flexible perovskite solar cell-driven photo-rechargeable lithium-ion capacitor for self-powered wearable strain sensors. Nano Energy 60:247–256

  4. 4.

    Xie JQ, Ji YQ, Kang JH, Sheng JL, Mao DS, Fu XZ, Sun R, Wong CP (2019) In situ growth of Cu (OH)2@FeOOH nanotube arrays on catalytically deposited Cu current collector patterns for high-performance flexible in-plane micro-sized energy storage devices. Energy Environ Sci 12:194–205

  5. 5.

    Zhang PP, Wang FX, Yu MH, Zhuang XD, Feng XL (2018) Two-dimensional materials for miniaturized energy storage devices: from individual devices to smart integrated systems. Chem Soc Rev 47(19):7426–7451

  6. 6.

    Liang Y, Zhao F, Cheng ZH, Deng YX, Xiao YK, Cheng HH, Zhang PP, Huang YX, Shao HB, Qu LT (2018) Electric power generation via asymmetric moisturizing of graphene oxide for flexible, printable and portable electronics. Energy Environ Sci 11(7):1730–1735

  7. 7.

    Sun HT, Mei L, Liang JF, Zhao ZP, Lee C, Fei HL, Ding MN, Lau J, Li MM, Wang C, Xu X, Hao GL, Papandrea B, Shakir I, Dunn B, Huang Y, Duan XF (2017) Three-dimensional holey-graphene/niobia composite architectures for ultrahigh-rate energy storage. Sci. 356(6338):599–604

  8. 8.

    Li WH, Zhou YL, Howell IR, Gai Y, Naik AR, Li SK, Carter KR, Watkins JJ (2018) Direct imprinting of scalable, high-performance woodpile electrodes for three-dimensional lithium-ion nanobatteries. ACS Appl Mater Interfaces 10(6):5447–5454

  9. 9.

    Fan TT, Sun P, Zhao J, Cui ZM, Cui GF (2019) Facile synthesis of three-dimensional ordered porous amorphous Ni-P for high-performance asymmetric supercapacitors. J Electrochem Soc 166(2):D37–D43

  10. 10.

    Hao ZM, Xu L, Liu Q, Yang W, Liao XB, Meng JS, Hong XF, He L, Mai LQ (2019) On-chip Ni–Zn microbattery based on hierarchical ordered porous Ni@Ni (OH)2 microelectrode with ultrafast ion and electron transport kinetics. Adv Funct Mater 29(16):1808470

  11. 11.

    Yao YW, Huang CJ, Chen X, Wei F, Feng HL (2017) Preparation and characterization of a porous structure PbO2-ZrO2 nanocomposite electrode and its application in electrocatalytic degradation of crystal violet. J Electrochem Soc 164(12):E367–E373

  12. 12.

    Li M, Meng JS, Li Q, Huang M, Liu X, Owusu KA, Liu ZA, Mai LQ (2018) Finely crafted 3D electrodes for dendrite-free and high-performance flexible fiber-shaped Zn–Co batteries. Adv Funct Mater 28(32):1802016

  13. 13.

    Xu JS, Sun YD, Lu MJ, Lin W, Jie Z, Tao E, Qian JH, Liu XY (2018) Fabrication of the porous MnCo2O4 nanorod arrays on Ni foam as an advanced electrode for asymmetric supercapacitors. Acta Mater 152:162–174

  14. 14.

    Song Y, Bian C, Hu JF, Li Y, Tong JH, Sun JZ, Gao GW, Xia SH (2019) Porous polypyrrole/graphene oxide functionalized with carboxyl composite for electrochemical sensor of trace cadmium (II). J Electrochem Soc 166(2):B95–B102

  15. 15.

    Sygletou M, Petridis C, Kymakis E, Stratakis E (2017) Advanced photonic processes for photovoltaic and energy storage systems. Adv Mater 29(39):1700335

  16. 16.

    Lin J, Peng ZW, Liu YY, Ruiz-zepeda F, Ye RQ, Samuel EG, Yacaman MJ, Yakobson BI, Tour JM (2014) Laser-induced porous graphene films from commercial polymers. Nat Commun 5:5714

  17. 17.

    El-kady MF, Ihns M, Li MP, Hwang JY, Mousavi MF, Chaney L, Lech AT, Kanera RB (2015) Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage. Proc Natl Acad Sci U S A 112(14):4233–4238

  18. 18.

    Chen Y, Xu JH, Yang YJ, Li SB, Yang WY, Peng TJ, Mao XL, Zhao YT (2015) PEDOT:PSS/graphene/PEDOT ternary film for high performance electrochemical electrode. J Mater Sci: Mater Electron. 26(11):8292-300

  19. 19.

    Martin DC, Wu JH, Charles MS, King Z, Spanninga SA, Richardson-burns S, Hendricks J, Yang JY (2010) The morphology of poly (3,4-ethylenedioxythiophene). Polym Rev 50(3):340–384

  20. 20.

    Liu R, Cho SI, Lee SB (2008) Poly (3,4-ethylenedioxythiophene) nanotubes as electrode materials for a high-powered supercapacitor. Nanotech. 19(21):215710

  21. 21.

    Mao XL, Yang WY, He X, Chen Y, Zhao YT, Zhou YJ, Yang YJ, Xu JH (2017) The preparation and characteristic of poly (3,4-ethylenedioxythiophene)/reduced graphene oxide nanocomposite and its application for supercapacitor electrode. Mater Sci Eng B 216:16–22

  22. 22.

    Zhang JT, Zhao XS (2012) Conducting polymers directly coated on reduced graphene oxide sheets as high-performance supercapacitor electrodes. J Phys Chem C 116(9):5420–5426

  23. 23.

    He DX, Marsden AJ, Li ZL, Zhao R, Xue WD, Bissett MA (2018) Fabrication of a graphene-based paper-like electrode for flexible solid-state supercapacitor devices. J Electrochem Soc 165(14):AA348–A3481

  24. 24.

    Lehtimäki S, Suominen M, Damlin P, Tuukkanen S, Kvarnström C, Lupo D (2015) Preparation of supercapacitors on flexible substrates with electrodeposited PEDOT/graphene composites. ACS Appl Mater Interfaces 7(40):22137–22147

  25. 25.

    William SJ, Richard EO (1958) Preparation of graphitic oxide. J Am Chem Soc 80(6):1339

  26. 26.

    El-kady MF, Kaner RB (2013) Scalable fabrication of high-power graphene micro-supercapacitors for flexible and on-chip energy storage. Nat Commun 4:1475

  27. 27.

    Mao XL, Xu JH, Xin H, Yang WY, Yang YJ, Lu X, Zhao YT, Zhou YJ (2018) All-solid-state flexible microsupercapacitors based on reduced graphene oxide/multi-walled carbon nanotube composite electrodes. Appl Surf Sci 435:1228–1236

  28. 28.

    El-kady MF, Strong V, Dubin S, Kaner RB (2012) Laser scribing of high performance and flexible graphene based electrochemical capacitors. Sci. 335(1326):1326–1330

  29. 29.

    Dan W, Jie Z, Dong WL, Chen HW, Xun H, Sun BQ, Chen LW (2013) Temperature dependent conductivity of vapor-phase polymerized PEDOT films. Synth Met 176:86–91

  30. 30.

    Tong LY, Skorenko KH, Faucett AC, Steven MB, Jian L, Mativetsky JM, William EB, Wayne EJ (2015) Vapor-phase polymerization of poly (3,4-ethylenedioxythiophene) (PEDOT) on commercial carbon coated aluminum foil as enhanced electrodes for supercapacitors. J Power Sources 297:195–201

  31. 31.

    Yu X, Su X, Yan K, Hu H, Peng M, Cai X, Zou D (2016) Stretchable, conductive, and stable PEDOT-modified textiles through a novel in situ polymerization process for stretchable supercapacitors. Adv Mater Technol 1(2):1600009

  32. 32.

    Xin Z, Dong MY, Zhang JX, Li YZ, Zhang QH (2016) Vapor-phase polymerization of poly (3, 4-ethylenedioxythiophene) nanofibers on carbon cloth as electrodes for flexible supercapacitors. Nanotechnology. 27:385705

  33. 33.

    Chien C, Hiralal P, Wang D, Huang I, Chen C, Chen C, Amaratunga GA (2015) Graphene-based integrated photovoltaic energy harvesting/storage device. Small. 11(24):2929–2937

  34. 34.

    Schaarschmidt A, Abdiaziz AF, Arun A, Helmy AS (2009) Influence of nonadiabatic annealing on the morphology and molecular structure of PEDOT−PSS films. J Phys Chem B 113(28):9352–9355

  35. 35.

    Strong V, Dubin S, El-kady MF, Lech A, Wang Y, Weiller BH, Richard BK (2012) Patterning and electronic tuning of laser scribed graphene for flexible all-carbon devices. ACS Nano 6(2):1395–1403

  36. 36.

    Su Y, Jia S, Du JH, Yuan JT, Liu C, Ren WC, Cheng HM (2015) Direct writing of graphene patterns and devices on graphene oxide films by inkjet reduction. Nano Res 8(12):3954–3962

  37. 37.

    Greczynski G, Kugler T, Salaneck WR (1999) Characterization of the PEDOT-PSS system by means of X-ray and ultraviolet photoelectron spectroscopy. Thin Solid Films 354(1/2):129–135

  38. 38.

    Han JH, Lin Y, Chen LY, Tsai Y, Ito Y, Guo XW, Hirata A, Fujita T, Esashi M, Gessner T, Chen MW (2015) On-chip micro-pseudocapacitors for ultrahigh energy and power delivery. Adv Sci 2(5):1500067

  39. 39.

    Xu HH, Hu XL, Yang HL, Sun YM, Hu CC, Huang YH (2014) Flexible asymmetric micro-supercapacitors based on Bi2O3 and MnO2 nanoflowers: larger areal mass promises higher energy density. Adv Energy Mater 5(6):1401882

  40. 40.

    Tang JY, Yuan P, Cai CL, Fu Y, Ma X (2016) Combining nature-inspired, graphene-wrapped flexible electrodes with nanocomposite polymer electrolyte for asymmetric capacitive energy storage. Adv Energy Mater 6(19):1600813

  41. 41.

    Pu X, Liu MM, Li LX, Han SC, Li X, Jiang C, Du C, Luo J, Hu W, Wang ZL (2016) Wearable textile-based in-plane microsupercapacitors. Adv Energy Mater 6(24):1601254

  42. 42.

    Song ZQ, Fan YY, Sun ZH, Han DX, Bao Y, Niu L (2017) A new strategy for integrating superior mechanical performance and high volumetric energy density into a Janus graphene film for wearable solid-state supercapacitors. J Mater Chem A 5:20797–20807

  43. 43.

    Si WP, Yan CL, Chen Y, Oswald S, Han LY, Schmidt OG (2013) On chip, all solid-state and flexible micro-supercapacitors with high performance based on MnOx/Au multilayers. Energy Environ Sci 6(11):3218–3223

  44. 44.

    Peng Y, Akuzum B, Kurra N, Zhao M, Alhabeb M, Anasori B, Kumbur EC, Alshareef HN, Ger M, Gogotsi Y (2016) All-MXene (2D titanium carbide) solid-state microsupercapacitors for on-chip energy storage. Energy Environ Sci 9(9):2847–2854

  45. 45.

    Le VT, Kim H, Ghosh A, Kim J, Chang J, Vu QA, Pham DT, Lee J, Kim S, Lee YH (2013) Coaxial fiber supercapacitor using all-carbon material electrodes. ACS Nano 7(7):5940–5947

  46. 46.

    Kou L, Huang TQ, Zheng BN, Han Y, Zhao XL, Gopalsamy K, Sun HY, Gao C (2014) Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics. Nat Commun 5:3754

  47. 47.

    Xiao X, Li TQ, Yang PH, Gao Y, Jin HY, Ni WJ, Zhan WH, Zhang XH, Cao YZ, Zhong JW, Gong L, Yen W, Mai WJ, Chen J, Huo KF, Chueh Y, Wang ZL, Zhou J (2012) Fiber-based all-solid-state flexible supercapacitors for self-powered systems. ACS Nano 6(10):9200–9206

  48. 48.

    Xie BH, Yang W, Lai WH, Lin W, Lin ZY, Zhang ZX, Zou PC, Yang X, Zhou S, Yang C, Kang FY, Wong CP (2016) Laser-processed graphene based micro-supercapacitors for ultrathin, rollable, compact and designable energy storage components. Nano Energy 26:276–285

  49. 49.

    Jiang WC, Zhai SL, Qian QH, Yuan Y, Karahan HE, Wei L, Goh KL, Ng AK, Wei J, Chen Y (2016) Space-confined assembly of all-carbon hybrid fibers for capacitive energy storage: realizing a built-to-order concept for micro-supercapacitors. Energy Environ Sci 9(2):611–622

  50. 50.

    Hou JG, Wu YZ, Cao SY, Sun YQ, Sun LC (2017) Active sites intercalated ultrathin carbon sheath on nanowire arrays as integrated core–shell architecture: highly efficient and durable electrocatalysts for overall water splitting. Small. 13(46):1702018

  51. 51.

    Hou JG, Sun YQ, Wu YZ, Cao SY, Sun LC (2017) Promoting active sites in core–shell nanowire array as Mott–Schottky electrocatalysts for efficient and stable overall water splitting. Adv Funct Mater 28(4):1704447

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Acknowledgements

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Funding

This work was supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. 51477026, 61471085, and 61774030), the National Science Funds for Creative Research Groups of China (Grant No. 61421002), Chongqing Postdoctoral Science Special Foundation (Grant No. Xm2017051), Chongqing Engineering Research Center of New Energy Storage Devices and Applications (Grant Nos. KF20170202 and KF20180202), and the Scientific Research Project of Chongqing University of Arts and Sciences (Grant Nos. R2016DQ11 and P 2016DQ14).

Author information

XM performed the experiments and was a major contributor in writing the manuscript. XH, JX, WY, HL, YY, and YZ participated in the discussion of the experiment. All authors read and approved the final manuscript.

Correspondence to Jianhua Xu.

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Keywords

  • Vapor phase polymerization
  • Microsupercapacitors
  • Energy storage
  • Array devices