Recoverable Wire-Shaped Supercapacitors with Ultrahigh Volumetric

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Recoverable wire-shaped supercapacitors with ultrahigh volumetric energy density for multifunctional portable and wearable electronics Minjie Shi, Cheng Yang, Xuefeng Song, Jing Liu, Liping Zhao, Peng Zhang, and Lian Gao ACS Appl. Mater. Interfaces, Just Accepted Manuscript • Publication Date (Web): 08 May 2017 Downloaded from http://pubs.acs.org on May 11, 2017

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ACS Applied Materials & Interfaces

Recoverable wire-shaped supercapacitors with ultrahigh

volumetric

multifunctional

energy

portable

density

and

for

wearable

electronics Minjie Shi, Cheng Yang, Xuefeng Song*, Jing Liu, Liping Zhao, Peng Zhang, Lian Gao*

State Key Laboratory for Metallic Matrix Composite Materials, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China

KEYWORDS shape memory, recoverable, wearable, wire-shaped supercapacitors, ultrahigh energy density

ABSTRACT Wire-shaped supercapacitors (SCs) based on shape memory materials are of considerable interest for next-generation portable and wearable electronics. However, the bottleneck in this field is how to develop the devices with excellent electrochemical performance, while well-maintaining recoverability and flexibility. Herein, a unique asymmetric electrode concept has been put forward to fabricate smart wire-shaped SCs with ultrahigh energy density, which is realized by using

ACS Paragon Plus Environment


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porous carbon dodecahedra coated on NiTi alloy wire and flexible graphene fiber as yarn electrodes. Notably, the wire-shaped SCs not only exhibit high flexibility that can be readily woven into the real clothing, but also represent the available recoverable ability. When irreversible plastic deformations happen, the deformed shape of the devices can automatically resume the initial predesigned shape in warm environment (about 35 °C). More importantly, the wire-shaped SCs act as the efficient energy storage devices, which display high volumetric energy density (8.9 mWh/cm3), volumetric power density (1080 mW/cm3), strong durability in multiple mechanical states, and steady electrochemical behavior after repeated shape recovery processes. Considering relative facile fabrication technology and excellent electrochemical performance, this asymmetric electrode strategy produced smart wire-shaped supercapacitors is desirable for multifunctional portable and wearable electronics.

INTRODUCTION Smart wire-shaped supercapacitors (SCs) based on shape memory materials (SMMs) have attracted wide research interest in portable and wearable electronics, which is owing to their efficient deformation recoverability, high flexibility and weavability 1-3. As a kind of novel intelligent material, SMMs can easily resume their predesigned shapes through reversible phase transformation

3, 4

. Specifically, the

deformed SMMs can return to memorial shapes when thermally triggered above their corresponding phase transition temperature. The fascinating feature endows the SMMs with reusable and restorable ability, which are suitable to be used as electrode for smart wire-shaped SCs. Recently, shape-memory polymers, such as polyaniline


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and polyurethane, have been utilized in SCs. Zhong et al. fabricated a shape memory polymer fiber via wet-spinning method 3. Polymer fiber followed by the layer by layer coating of carbon nanotubes (CNTs) and deposited polyaniline results in wire-shaped SCs with shape memory effect. Deng et al.constructed smart wire-shaped SCs by wrapping aligned CNTs onto a shape-memory polyurethane. The fabricated devices can be transformed into required shapes and recover to the original shapes automatically once the temperature exceeds the thermal transition temperature 2. However, the shape-memory polymers mostly suffer from the unavoidable problem, that is high thermal transition temperature (~ 80 °C), thereby leading to the poor applicability of resulting wire-shaped SCs. By contrast, nickel–titanium alloy (NTA) as electrode has been burgeoningly investigated

in

shape-memory

SCs,

phase-transition temperature (< 40 °C) elasticity/flexibility, conventional alloys

better 6, 8, 9

corrosion

which 5-7

is

due

to

its

moderate

. Meanwhile, NTA exhibits higher

resistance

and

biocompatibility

than

. Very recently, Liu et al. successfully fabricated high

performance planar SCs with body temperature inducible shape memory ability, in which graphene coated NTA flake as the negative electrode and ultrathin MnO2/Ni film as the positive electrode 5. Yang et al. presented a type of shape-memory wire-shaped SCs, which is realized by using PPy-MnO2-NTA wire and stainless yarn as electrodes

9

. Despite the progress mentioned above, the performance of

shape-memory SCs based on NTA electrodes is still limited, which is mainly plagued by the unsatisfactory flexibility and electrochemical inertia of the used opposite electrodes, such as Ni film or stainless yarn electrode. As a consequence, NTA shape-memory SCs mostly suffer from poor wearing comfortability and low volumetric energy density (most < 2 mWh/cm3).



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To improve the performance of shape-memory wire-shaped SCs, the opposite electrode with high flexibility and electrochemical activity is urgently desirable. As well known, carbonaceous fibers are highly conductive, ultra-light, and can directly contribute to energy storage

10-13

. In particular, graphene fiber (g-fiber) exhibits high

mechanical flexibility, excellent electrochemical activity, relatively facile fabrication, and pronounced electrical conductivity 14-16. Because of these features, flexible g-fiber as yarn electrode is supposed to exhibit outstanding electrochemical performance and high volumetric energy/power density, which sheds light on enhancing the performance of wire-shaped SCs

16-18

. Nevertheless, to the best of our knowledge,

there have been no reports on the construction of NTA electrode integrated with flexible g-fiber opposite electrode used for shape-memory wire-shaped SCs. Herein, an ingenious asymmetric electrode concept has been put forward to fabricate smart wire-shaped SCs with ultrahigh energy density, which is realized by using porous carbon dodecahedra coated on NTA wire (c-NTAw) as an electrode and flexible g-fiber as opposite electrode. Such a unique configuration of the wire-shaped SCs has following characteristics: on the one hand, shape memorial c-NTAw electrode provides as-fabricated devices with available recoverable ability. Meanwhile, porous carbon dodecahedral particles on NTA wire provide abundant electro-active sites; on the other hand, highly flexible g-fiber electrode further improves the mechanical stability, flexibility, and electrochemical capacitance of whole devices. Profiting from the rational design, the wire-shaped SCs exhibit outstanding electrochemical performance, omni-directional flexibility and distinctive shape recoverable ability: (1) the integrated devices exhibit wide voltage range and ultrahigh volumetric density of 8.9 Wh/cm3. To our knowledge, so far this energy density is almost the highest value compared to recently reported wire-shaped SCs 19-21; (2) the whole devices are highly


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flexible, mechanically stable (tensile strength up to 95.8 MPa), and randomly bendable without decline of electrochemical performance; (3) the fabricated devices dramatically represent the effective recoverable ability. When irreversible plastic deformation happens, the deformed shape of the devices can automatically resume the initial predesigned shape only in the warm environment (about 35 °C). More importantly, the electrochemical behaviors of the devices exhibit no obvious degradation after repeated shape recovery. On the basis of above merits, the smart wire-shaped SCs can be easily woven into the real clothing, which not only act as the efficient energy storage devices, but also exhibit the intelligent shape memory property, thus providing a diversity of potential applications in portable and wearable electronics.

RESULTS AND DISCUSSION

Figure 1. (a) Digital photograph of flexible c-NTAw electrode. (b) Real-time image of the shape-recovery process of c-NTAw electrode. (c-e) FESEM images with different magnifications of the carbon layer coated on NTA wire. Inset in (e) shows that the carbon layer is composed of numerous carbon particles with dodecahedral architecture.



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Figure 1a represents the digital photograph of c-NTAw electrode. The prepared electrode can be bent without any peeling, suggesting the excellent flexibility of the electrode and the good adhesion between NTA wire and coated carbon layer. Figure 1b shows the shape memory effect of c-NTAw electrode. Owing to the moderate phase-transition temperature of NTA wire, the deformed shape of c-NTAw electrode can automatically return to initial straight shape (< 1 min) when the temperature reaches to 35 °C. Figure 1c-e exhibit the representative FESEM images of c-NTAw electrode in different magnifications. Figure 1c shows that the NTA wire (~350 um diameter) is entirely wrapped by carbon layer (~50 um thickness) to form a typical coaxial cable-like electrode

22

. As shown in Figure 1d, the outside carbon layer is

homogeneous, dense with almost no cracks. FESEM image of high magnification indicates that the carbon layer is made up of numerous carbon particles with unique dodecahedral

architecture.

These carbon

dodecahedra

derived

from

metal-organic frameworks exhibit high porosity and large surface area of 1620 m 2/g (Figure S1), which can act as abundant active sites to provide remarkable double-layer capacitance of the electrode. The electro-active carbon layer coated on the NTA wire exhibits excellent electrochemical performance and large specific volumetric capacitance of 81.7 F/cm3 in ionic liquid electrolyte (Figure S2). Meanwhile, the polyhedral structure of porous carbon can effectively avoid the stacking/aggregation problem (due to multi-faces), dramatically improving the stability of carbon layer during the electrochemical process

23, 24

. Detailed

characterization of NTA wire and porous carbon particles are described in Figure S1-3. Figure 2a displays the optical photo of flexible g-fiber electrode. The resultant g-fiber electrode exhibits the excellent stretchable and bendable ability (Figure 2b).


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More interestingly, the size of g-fiber can be controlled by simply using the pipeline with predesigned inner diameter or length. Accordingly, a series of flexible g-fiber samples with various sizes are easily obtained (Figure S4). FESEM images (Figure 2c-e) show that the surface of g-fiber (~300 um of diameter) is rough and wrinkled, which greatly increases the specific area of electric double layer for the capacitive energy storage

25, 26

. The highly flexible g-fiber electrode can deliver a considerably

large volumetric specific capacitance of 95.1 F/cm3 in ionic liquid electrolyte (Figure S2).

Figure 2. (a, b) Optical photos of g-fiber electrode with excellent stretchable and bendable ability. (c-e) FESEM images with different magnifications of the g-fiber electrode. Inset in (e) shows that the g-fiber is made up of crumpled and wrinkled nanosheets.



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Figure 3. (a) Schematic illustration of assembling the wire-shaped SCs with shape memory function. (b) Cross-section FESEM image of the devices. (c, d) Optical photos of the flexible wire-shaped SCs.

Figure 4a shows the CV curves of smart wire-shaped SCs in the straight state at different scan rates ranging from 10 to 200 mV/s. All the CV curves without any overpotential stabilized in the range from 0 to 3 V, demonstrating that the assembled devices can operate within a high working voltage of 3 V. Meanwhile, the rectangle-like CV curves at different scan rates indicate the ideal capacitive behavior and fast charge–discharge property of the wire-shaped SCs

35-37

. It is also supported

by the near-triangle GCD curves at different current densities from 100 to 800 mA/cm3 (Figure 4b). The negligible “IR drop” of discharge curve strongly evinces the favorable resistive behavior of the devices (Figure S8)

38, 39

. As we know, the

volumetric power/energy density based on total volume is a more meaningful


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parameter than the gravimetric power/energy density for evaluating the energy storage performance of the micro- and wire-shaped devices

40, 41

. By calculating, the

wire-shaped SCs deliver a volumetric capacitance of 7.1 F/cm3 at the current density of 100 mA/cm3, which contributes to achieve a maximum volumetric energy density up to 8.9 mWh/cm3 (Figure 4c). Such an energy storage performance is considerably superior than that of previously reported wire-shaped SCs (most < 4 mWh/cm3, Table S1) and planar flexible SCs (most < 2 mWh/cm3) 42, 43, about several ten times higher than that of commercially available SCs (2.75 V/44 mF and 5.5 V/100 mF, < 1 mWh/cm3), even comparable to that of 4 V/500 µAh thin-film lithium batteries (~9 mWh/cm3)

19, 43

. Meanwhile, the maximum volumetric power density of the

wire-shaped SCs is 1080 mW/cm3, which is comparable to that of commercially available SCs and much higher than that of thin-film lithium batteries (Figure 4c) 44, 45 The excellent electrochemical behaviors of wire-shaped SCs are attributed to two aspects: on the one hand, the large specific surface area and abundant mesoporous channels of electrode are favorable for the accumulation of electron charges and the diffusion of electrolyte ions during the electrochemical process, which are conducive to the enhancement of electrochemical behaviors of the wire-shaped SCs; on the other hand, the resulting porous carbon and g-fiber electrodes possess high electrical conductivity of 560 S/m and 980 S/m, respectively. These are beneficial for the large volumetric capacitance of electrode at high current densities, which greatly ensure the good rate performance of the wire-shaped SCs. The smart wire-shaped SCs were further subjected to the mechanical bending tests. As shown in Figure 4d, the CV curves of the wire-shaped SCs at various bending angles exhibit almost similar capacitive behavior to that of the straight state. During the statical or dynamic bend, the light-emitting-diode (LED) indicator still



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emits light (Supplementary Movie 1), indicating the great electrochemical reliability with omni-directional flexibility of the devices. Moreover, in order to measure the long cycle performance, the wire-shaped SCs were sealed into PDMS to avoid the water entered into the devices. As shown in Figure 4e, the cycling stabilities of wire-shaped SCs in the straight and bending states reveal the high retention about 93% and 89% after 100000 cycles. The strong durability of as-fabricated devices is considerably better than that of previously reported SCs based on ionogel electrolyte 31, 46-48

. Undoubtedly, the wire-shaped SCs represent the satisfactory energy

storage/delivery capacity and stable electrochemical performance in various mechanical states, which are highly desirable for high performance flexible energy storage devices. More information about the cycle performances of the unpacked and packaged devices at the current density of 200 mA/cm3 after 100000 cycles are shown in Figure S9.

Figure 4. (a) CV curves at various scan rates (10~200 mV/s), (b) GCD curves at different current densities (100~800 mA/cm3) of the wire-shaped SCs. (c) Ragone plot


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of as-fabricated wire-shaped SCs compared with the commercially available energy storage devices, previously reported wire-shaped SCs and planar flexible SCs. (d) CV curves of the wire-shaped SCs under different curvatures of 0º, 40º, 80º, and 120º scanning at 100 mV/s. (e) Cycle performances of the packaged devices in the straight and bending states at the current density of 200 mA/cm3 after 100000 cycles.

To evaluate the shape memory function of wire-shaped SCs, a series of distinctive experiments were carried out using the pre-designed devices with memorial straight shape. As shown in Figure 5a, the irreversible deformed shape of devices can automatically resume the initial straight shape in a short time after mild heat treatment (~ 35 °C). The complete shape memory recovery process is also available as video in Supplementary Movie 2 and 3. Besides the perfect shape restoration, the electrochemical behaviors of the wire-shaped SCs exhibit no obvious degradation after 100 deformation–restoration cycles (Figure 5b). Remarkably, after performing up to 200 cycles, the shape recovery ratio still maintains a high value of 92%, while the capacitance retention also reveals a satisfactory value by reaching 88% (Figure 5c and Figure S8). The efficient recoverability of as-fabricated wire-shaped SCs is apparently better than that of previously reported shape-memory SCs

2, 5, 8, 9

, which

are mainly attributed to the following aspects: on the one hand, the c-NTAw electrode represents a moderate phase-transition temperature, which makes the wire-shaped SCs easy to achieve the effective shape memory ability; on the other hand, highly flexible g-fiber with low weight exhibits almost no hysteretic elasticity, and unable to hamper the shape recovery process of the whole devices. These results sufficiently demonstrate that the smart wire-shaped SCs not only possess the fascinating shape memory property, but also maintain the steady electrochemical performance during



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the process of repeated deformation recovery. These characteristics endow our devices with outstanding recoverable ability, which effectively alleviates the problem about irreversible plastic deformation of electronic devices in practical application. Moreover, as shown in Figure S10, the electrochemical performance of fabricated asymmetric wire-shaped SCs is superior to that of symmetric wire-shaped SCs with ionogel electrolyte. Thus, the asymmetric electrode concept of wire-shaped SCs greatly ensures the good electrochemical behaviors and effective shape memory function of fabracated devices.

Figure 5. (a) Real-time image of the shape-recovery process of wire-shaped SCs. (b) CV curves of the devices before and after shape recovery scanning at 100 mV/s. (c) Capacitance retention and shape recovery ratio after different shape recovery cycles.


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Figure 6. (a) Photograph of the wire-shaped SCs woven into the cotton fabric. (b) Real-time image of the shape-recovery process of the smart cotton fabric under a high outdoor temperature. (c, d) Photograph of the real clothing made up of wire-shaped SCs showing the efficient energy storage and shape memory capacity. (e) Schematic demonstration of the smart clothing for potential application.

Due to the wire-shaped SCs with high flexibility at room temperature, the devices can be readily knitted with traditional yarns in cotton fabric (Figure 6a). As shown in Figure 6b, it is found that the curved fabric can recover to its initial flat state in an outdoor ambience (especially in hot summer), which is ascribed to the shape memory effect of wire-shaped SCs in the fabric. For a real application, the wire-shaped SCs can be woven into the clothing. It is obvious that the sleeve of clothing woven with the devices can perform arbitrary shape in need (Supplementary Movie 4), indicating the versatilely wearable performance of the devices in practical application. The perfect integration of the fabricated devices and textiles are beneficial from the soft



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and supple structure of highly flexible c-NTAw and g-fiber electrodes. Besides the reliable weavability of the wire-shaped SCs, the devices woven into the clothing not only act as the efficient energy storage devices (Figure 6c), but also exhibit the intelligent shape recovery ability (Figure 6d). Moreover, it is noteworthy that the wire-shaped SCs represent a moderate deformation–restoration temperature of around 35 °C, which is close to human body temperature. The sleeve of clothing woven with our devices can perform a shape recovery process merely relying on the heat generated by the human body without additional heating. In this case, the sleeve can realize automatic self-open when people are doing strenuous exercise, which is favorable for the heat dissipation to make them feel comfortable (Figure 6e). Based on the above results, it is obvious that the smart shape memorial textiles can be endowed with more practical functionalities. To meet high voltage demand for practical application, the wire-shaped SCs with in-series system can be simply and effectively fabricated

49, 50

. As schematically

demonstrated in Figure 7a, a thicker NTA wire was used and it was set into a “hook” shape (the pre-designed shape) in advance. Then, porous carbon dodecahedra was continuously

coated

onto

the

surface

of

NTA

wire

with

certain

interval between each active part, and followed by wrapping ionogel electrolyte and winding g-fiber electrode to construct in-series configuration containing two units. The part between the two units is pure NTA wire segment, which is left to act as guide line to connect two sections. As shown in Figure 7b, a pair of LED indicators can easily light up owing to the high working voltage of whole devices. Meanwhile, the fabricated devices exhibit remarkable shape memory effect, which can be readily deformed to arbitrary shape in need and rapidly recovered after mild heat irradiation (Figure 7c, Supplementary Movie 5). Benefiting from these features combining with


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the “hook” structural design, the wire-shaped SCs hold promising for hangable and portable energy storage devices (Figure 7d). By using the same method, circular wire-shaped SCs with in-series configuration can be also assembled (Figure S11a), which represent the high operation voltage and innovative shape memory ability for applications (Figure S11b and c). Accordingly, the wire-shaped SCs with unique in-series arrangement not only exhibit tiny volume and enhanced output voltage, which can serve as the smart power supply for mobile electronic devices (eg. headsets, watches and sport bracelets), but also possess the effective shape memory function that ensure the convenience and security when worn in daily life.

Figure 7. (a) Schematic of the fabrication for the “hook” structural wire-shaped SCs with the in-series system containing two units. (b) Two LED indicators can light up with the whole devices. (c) Real-time image of the shape-recovery process of the in-series wire-shaped SCs. (d) Photograph of the promising application of wire-shaped SCs in hangable and portable electronic.



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CONCLUSIONS In summary, an ingenious asymmetric design of smart wire-shaped SCs with shape memory function has been developed, using porous carbon dodecahedra coated on NiTi alloy wire and flexible graphene fiber as yarn electrodes, respectively. As a result, the highly flexible devices exhibit ultrahigh energy density of 8.9 mWh/cm3, power density of 1080 mW/cm3, and excellent reliability in different mechanical states. More interestingly, the as-fabricated devices can promptly restore their irreversible plastic deformation to the initial memorial state, while the capacitive performance remains nearly unchanged. The potential risks of structural fracture can be nipped in the bud owing to the distinctive shape memory of devices. Furthermore, the smart textiles woven with the as-obtained wire-shaped SCs are endowed with more practical functionalities besides energy storage. Therefore, this work represents a quantum leap forward in search of high-performance powering wearable electronics.

METHODS Synthesis of porous carbon. Firstly, the original NTA wire was repeatedly cleaned with acetone, ethanol and deionized water, and then heat-treated at 300 °C for 5 h in Ar atmosphere to remove the work hardening and set desired shapes. Afterwards, porous carbon dodecahedra are derived from zeolitic imidazole metal–organic frameworks (ZIF-8). Typically, zinc acetate (48 mM) was uniformly dissolved in 200 mL methanol solution containing polyvinyl pyrrolidone (0.4 mM). The mixture was then placed in refrigerator (~ 4 °C) for 1 h. Meanwhile, 200 mL 2-Methylimidazole (160 mM) methanol solution was cooled in the same condition. Sequently, the two


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solutions were mixed and incubated at room temperature overnight. The ZIF-8 was received under vacuum drying after centrifugation and washing, which was then calcined at 900 °C for 5 h under Ar atmosphere to obtain porous carbon dodecahedra. After that, the mixture of porous carbon dodecahedra (85 wt%), acetylene black (5 wt%), and PTFE (10 wt%) was repeatedly brushed onto the surface of NTA wire, followed by a drying-solidifying process in the oven to form c-NTAw electrode. Synthesis of g-fiber. Graphene oxide (GO) was synthesized using natural graphite (Alfa Aesar, 325 mesh, 99.8%) by a modified Hummer’s method 51-53. Afterwards, 50 mg ascorbic acid (VC) was added into the 10 ml graphene oxide (1.5 mg/ml) solution under stirred for 5 min. The resulting mixture solution was injected into a glass pipe with the diameter of 5 mm, followed by sealing at both ends. After having reacted at 80 °C for 1 h, the glass pipe with both ends open was placed at 40 °C in air for drying g-fiber. Finally, the dried g-fiber was heated at 180 °C for 2 h under Ar atmosphere to remove the residual VC. Assembling of the wire-shaped SCs. Ionogel electrolyte was prepared with 0.5 g Poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)), 2 g EMIMBF4 ionic liquid and 4 mL of acetone solution. c-NTAw electrode was immersed into the above solution for 2 min. After being taken out, c-NTAw electrode was completely encapsulated in the P(VDF-HFP)/EMIMBF4 ionogel electrolyte, which was then simply twined by g-fiber opposite electrode. At this moment, two intertwined electrodes were further coated by slight electrolyte solution again to firmly assemble the asymmetric wire-shaped SCs. In order to measure the long cycle performance, the



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wire-shaped SCs were sealed into polydimethylsiloxane (PDMS) to avoid the water entered into the devices. PDMS was prepared in detail as follows: 1 g of curing agent was added into 10 g of silicone elastomer base, then stirred until a large number of bubbles were formed. Uniform PDMS layer wrapped on wire-shaped SCs was obtained after vacuum treatment at room temperature (Inset in Figure S9). Characterization. Field emission scanning electron microscope (FESEM, FEI Sirion 200) and Transmission electron microscopy (TEM, JEM-2010F) were carried out to characterize the morphology of the samples. X-ray diffraction (XRD) patterns were characterized on a powder XRD system with Cu Ka radiation. All the electrochemical measurements were carried out using a VMP3 multi-functional electrochemical analysis instrument (Bio-Logic, France). Electrochemical behaviors were investigated by

cyclic

voltammetry

(CV),

galvanostatic

charge–discharge

(GCD)

and

electrochemical impedance (EIS) methods using a VMP3 multi-functional electrochemical analysis instrument (Bio-Logic, France). The CV and GCD tests were measured at various scan rates and current densities. The EIS plots were performed in the frequency ranging from 0.05 Hz to 100 kHz with 5 mV AC amplitude. The volumetric specific capacitance, volumetric energy and power density of wire-shaped SCs were calculated from the galvanostatic discharge curve according to the two-electrode systematic calculation method: C v =IΔ t/VΔ U

(1)

E v =C v (Δ U) 2 /7.2

(2)

P v =3600·E v /Δ t

(3)


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where Cv (F/cm3) is the volumetric specific capacitance, Ev (mWh/cm3) is the volumetric energy density, Pv (mW/cm3) is the volumetric power density, I is the discharge current, Δt is the discharge time, ΔU is the voltage variation during the discharge process after “IR drop”, V (cm3) is the totale volume of the devices. Additionally, the electrochemical performance and specific volumetric capacitance of single c-NTAw or g-fiber electrode is measured and calculated according to the three-electrode systematic method in EMIMBF4 ionic liquid electrolyte.

ASSOCIATED CONTENT

Supporting

Information:

Figures

giving

(1)

TEM

images,

Nitrogen

adsorption/desorption isotherm and XRD pattern of the porous carbon particles; (2) CV and GCD curves of the c-NTAw and g-fiber electrodes in EMIMBF4 ionic liquid electrolyte; (3) FESEM image, Digital photograph of flexibility and knittability of the NTA wires; (4) Digital photograph, XRD pattern and Nitrogen adsorption/desorption isotherm of the g-fiber electrode, and optical photos of the preparation of g-fiber electrodes with various sizes; (5) Digital photos and FESEM image of c-NTAw electrode encapsulated in ionogel electrolyte; (6) Schematic diagrams of side-surface and cross-section structure of wire-shaped SCs; (7) Typical stress-strain curve of wire-shaped SCs; (8) GCD curves and Nyquist plots of the wire-shaped SCs at initial state and after recovery (100 and 200 cycles); (9) Cycle performances of the unpacked and packaged wire-shaped SCs after 100000 cycles; (10) CV curves of the asymmetric and symmetric wire-shaped SCs with ionogel electrolyte; (11) Digital



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Page 20 of 27

images of the fabrication and application of “circle” structural wire-shaped SCs with the in-series arrangement. Table giving (1) Energy density of state-of-the-art wire-shaped SCs comparison with our results. This material is available free of charge via the internet at http://pubs.acs.org.

AUTHOR INFORMATION

Corresponding Author *Email (X. F. Song): [email protected]. *Email (L. Gao): [email protected]. Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT This

work

was

supported

by the

Shanghai

Municipal

Natural

Science

Foundation(17ZR1414900), the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(SKL201604SIC), and the National Natural Science Foundation of China (51302169, 51502170).

REFERENCES

1.

Huang, Y.; Zhu, M. S.; Huang, Y.; Pei, Z. X.; Li, H. F.; Wang, Z. F.; Xue, Q.; Zhi C.Y. Multifunctional Energy Storage and Conversion Devices. Adv. Mater. 2016,


Page 21 of 27

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


28, 8344-8364. 2.

Deng, J. E.; Zhang, Y.; Zhao, Y.; Chen, P. N.; Cheng, X. L.; Peng, H. S. A Shape-Memory Supercapacitor Fiber. Angew. Chem. Int. Ed. 2015, 54, 15419-15423.

3.

Zhong, J.; Meng, J.; Yang, Z. Y.; Poulin, P.; Koratkar, N. Shape Memory Fiber Supercapacitors. Nano Energy 2015, 17, 330-338.

4.

Tai, Z. X.; Yan, X. B.; Xue, Q. J. Shape-Alterable and -Recoverable Graphene/Polyurethane

Bi-Layered

Composite

Film

for

Supercapacitor

Electrode. J. Power Sources 2012, 213, 350-357. 5.

Liu, L. Y.; Shen, B. S.; Jiang, D.; Guo, R. S.; Kong, L. B.; Yan, X. B. Watchband-Like Supercapacitors with Body Temperature Inducible Shape Memory Ability. Adv. Energy Mater. 2016, 610, 1002/aenm.201600763.

6.

Elahinia, M. H.; Hashemi, M.; Tabesh, M.; Bhaduri, S. B. Manufacturing and Processing of NiTi Implants: A Review. Prog. Mater. Sci. 2012, 57, 911-946.

7.

Hao, S. J.; Cui, L. S.; Jiang, J.; Guo, F. M.; Xiao, X. H.; Jiang, D. Q.; Yu, C.; Chen, Z. H.; Zhou, H.; Wang, Y. D.; Liu, Y. Z.; Brown, D. E.; Ren, Y. A Novel Multifunctional NiTi/Ag Hierarchical Composite. Sci. Rep. 2014, 4, 5267-5273.

8.

Huang, Y.; Zhu, M. S.; Li, H. F.; Pei, Z. X.; Xue, Q.; Liao, Z.; Wang, Z. F.; Zhi, C. Y. A Modularization Approach for Linear-Shaped Functional Supercapacitors. J. Mater. Chem. A 2016, 4, 4580-4586.

9.

Huang, Y.; Zhu, M. S.; Pei, Z. X.; Xue, Q.; Zhi, C. Y. A Shape Memory Supercapacitor and Its Application in Smart Energy Storage Ttextiles. J. Mater. Chem. A 2016, 4, 1290-1297.

10. Zhang,

Z.

Y.;

Xiao,

F.;

Wang,

S.

Hierarchically

Structured

MnO2/Graphene/Carbon Fiber and Porous Graphene Hydrogel Wrapped Copper Wire for Fiber-Based Flexible All-Solid-State Asymmetric Supercapacitors. J. Mater. Chem. A 2015, 3, 11215-11223. 11. Harrison D.; Qiu, F. L.; Fyson, J.; Xu, Y. M.; Evans P.; Southee, D. A Coaxial Single Fiber Supercapacitor for Energy Storage. Phys. Chem. Chem. Phys. 2013, 15, 12215-12219.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

12. Yu, D. S.; Zhai, S. L.; Jiang, W. C.; Goh, K. L.; Wei, L.; Chen, X. D.; Jiang, R. R.; Chen, Y. Transforming Pristine Carbon Fiber Tows into High Performance Solid-State Fiber Supercapacitors. Adv. Mater. 2015, 27, 4895-4901. 13. Wang, J.; Li, X. H.; Zi, Y. L.; Wang, S. H.; Li, Z. L.; Zheng, L.; Yi, F.; Li, S. M.; Wang, Z. L. A Flexible Fiber-Based Supercapacitor-Triboelectric-Nanogenerator Power System for Wearable Electronics. Adv. Mater. 2015, 27, 4830-4836. 14. Li, X. M.; Zhao, T. S.; Chen, Q.; Li, P. X.; Wang, K. L.; Zhong, M. L.; Wei, J. Q.; Wu, D. H.; Wei, B. Q.; Zhu, H. W. Flexible All Solid-State Supercapacitors Based on Chemical Vapor Deposition Derived Graphene Fibers. Phys. Chem. Chem. Phys. 2013, 15, 17752-17757. 15. Li, J. H.; Li, J. Y.; Li, L. F.; Yu, M.; Ma, H. J.; Zhang, B. W. Flexible Graphene Fibers Prepared by Chemical Reduction-Induced Self-Assembly. J. Mater. Chem. A 2014, 2, 6359-6362. 16. Chen, L. L.; Liu, Y.; Zhao, Y.; Chen, N.; Qu, L. T. Graphene-Based Fibers for Supercapacitor Applications. Nanotechnology 2016, 27, 135401-135420. 17. Huang, G. J.; Hou, C. Y.; Shao, Y. L.; Zhu, B. J.; Jia, B. P.; Wang, H. Z.; Zhang, Q. H.; Li, Y. G. High-Performance All-Solid-State Yarn Supercapacitors Based on Porous Graphene Ribbons. Nano Energy 2015, 12, 26-32. 18. Chen, Q.; Meng, Y. N.; Hu, C. G.; Zhao, Y.; Shao, H. B.; Chen, N.; Qu, L. T. MnO2-Modified Hierarchical Graphene Fiber Electrochemical Supercapacitor. J. Power Sources 2014, 247, 32-39. 19. Liu, L. B.; Yu, Y.; Yan, C.; Li, K.; Zheng, Z. J. Wearable Energy-Dense and Power-Dense Supercapacitor Yarns Enabled by Scalable Graphene-Metallic Textile Composite Electrodes. Nat. Commun. 2015, 6, 7260-7269. 20. Kou, L.; Huang, T. Q.; Zheng, B. N.; Han, Y.; Zhao, X. L.; Gopalsamy, K.; Sun, H. Y.; Gao, C. Coaxial Wet-Spun Yarn Supercapacitors for High-Energy Density and Safe Wearable Electronics. Nat. Commun. 2014, 5, 3754-3764. 21. Lee, J. A.; Shin, M. K.; Kim, S. H.; Cho, H. U.; Spinks, G. M.; Wallace, G. G.; Lima, M. D.; Lepro, X.; Kozlov, M. E.; Baughman, R. H.; Kim, S. J. Ultrafast Charge and Discharge Biscrolled Yarn Supercapacitors for Textiles and


Page 22 of 27

Page 23 of 27

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Microdevices. Nat. Commun. 2013, 4, 1970-1978. 22. Dong, X. L.; Guo, Z. Y.; Song, Y. F.; Hou, M. Y.; Wang, J. Q.; Wang, Y. G.; Xia, Y.

Y.

Flexible

and

Wire-Shaped

Micro-Supercapacitor

Based

on

Ni(OH)2-Nanowire and Ordered Mesoporous Carbon Electrodes. Adv. Funct. Mater. 2014, 24, 3405-3412. 23. Salunkhe, R. R.; Young, C.; Tang, J.; Takei, T.; Ide, Y.; Kobayashi, N.; Yamauchi, Y. A High-Performance Supercapacitor Cell Based on ZIF-8-Derived Nanoporous Carbon Using an Organic Electrolyte. Chem. Commun. 2016, 52, 4764-4767. 24. Gao, Y. L.; Wu, J. X.; Zhang, W.; Tan, Y. Y.; Gao, J.; Zhao, J. C.; Tang, B. H. J. The Calcined Zeolitic Imidazolate Framework-8 (ZIF-8) Under Different Conditions as Electrode for Supercapacitor Applications. J Solid State Electrochem. 2014, 18, 3203-3207. 25. Dong, Z. L.; Jiang, C. C.; Cheng, H. H.; Zhao, Y.; Shi, G. Q.; Jiang, L.; Qu, L. T. Facile Fabrication of Light, Flexible and Multifunctional Graphene Fibers. Adv. Mater. 2012, 24, 1856-1861. 26. Qu, G. X.; Cheng, J. L.; Li, X. D.; Yuan, D. M.; Chen, P. N.; Chen, X. L.; Wang, B.; Peng, H. S. A Fiber Supercapacitor with High Energy Density Based on Hollow Graphene/Conducting Polymer Fiber Electrode. Adv. Mater. 2016, 28, 3646-3652. 27. Shi, M. J.; Kou, S. Z.; Yan, X. B. Engineering the Electrochemical Capacitive Properties of Graphene Sheets in Ionic-Liquid Electrolytes by Correct Selection of Anions. Chemsuschem 2014, 7, 3053-3062. 28. Le Bideau, J.; Viau, L.; Vioux, A. Ionogels, Ionic Liquid Based Hybrid Materials. Chem. Soc. Rev. 2011, 40, 907-925. 29. MacFarlane, D. R.; Tachikawa, N.; Forsyth, M.; Pringle, J. M.; Howlett, P. C.; Elliott, G. D.; Davis, J. H.; Watanabe, M.; Simon, P.; Angell, C. A. Energy Applications of Ionic Liquids. Energy Environ. Sci. 2014, 7, 232-250. 30. Choi, B. G.; Huh, Y. S.; Hong, W. H.; Kim, H. J.; Park, H. S. Electrochemical Assembly of MnO2 on Ionic Liquid-Graphene Films into a Hierarchical Structure



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 27

for High Rate Capability and Long Cycle Stability of Pseudocapacitors. Nanoscale 2012, 4, 5394-5400. 31. Yang, X.; Zhang, F.; Zhang, L.; Zhang, T. F.; Huang, Y.; Chen, Y. S. A High-Performance Graphene Oxide-Doped Ion Gel as Gel Polymer Electrolyte for All-Solid-State Supercapacitor Applications. Adv. Funct. Mater. 2013, 23, 3353-3360. 32. El-Kady, M. F.; Kaner, R. B. Scalable Fabrication of High-Power Graphene Micro-Supercapacitors for Flexible and On-Chip Energy Storage. Nat. Commun. 2013, 4, 1475-1484. 33. Fuller, J.; Breda, A. C.; Carlin, R. T. Ionic Liquid-Polymer Gel Electrolytes from Hydrophilic and Hydrophobic Ionic Liquids. J. Electroanal. Chem. 1998, 459, 29-34. 34. Cheng, Y.; Wang, R. R.; Sun, J.; Gao, L. Highly Conductive and Ultrastretchable Electric Circuits from Covered Yarns and Silver Nanowires. ACS Nano 2015, 9, 3887-3895. 35. Kim, T. Y.; Lee, H. W.; Stoller, M.; Dreyer, D. R.; Bielawski, C. W.; Ruoff, R. S.; Suh,

K.

S.

High-Performance

Supercapacitors

Based

on

Poly(Ionic

Liquid)-Modified Graphene Electrodes. ACS Nano 2011, 5, 436-442. 36. Zhu, Y. W.; Murali, S.; Stoller, M. D.; Ganesh, K. J.; Cai, W. W.; Ferreira, P. J.; Pirkle, A.; Wallace, R. M.; Cychosz, K. A.; Thommes, M.; Su, D.; Stach, E. A.; Ruoff, R. S. Carbon-Based Supercapacitors Produced by Activation of Graphene. Science 2011, 332, 1537-1541. 37. Choi, B. G.; Chang, S. J.; Kang, H. W.; Park, C. P.; Kim, H. J.; Hong, W. H.; Lee, S.; Huh, Y. S. High Performance of a Solid-State Flexible Asymmetric Supercapacitor Based on Graphene Films. Nanoscale 2012, 4, 4983-4988. 38. Liu, W. W.; Yan, X. B.; Lang, J. W.; Xue, Q. J. Effects of Concentration and Temperature of EMIMBF4/Acetonitrile Electrolyte on the Supercapacitive Behavior of Graphene Nanosheets. J. Mater. Chem. A 2012, 22, 8853-8861. 39. Liu, W. W.; Yan, X. B.; Lang, J. W.; Xue, Q. J. Electrochemical Behavior of Graphene Nanosheets in Alkylimidazolium Tetrafluoroborate Ionic Liquid


Page 25 of 27

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Electrolytes: Influences of Organic Solvents and the Alkyl Chains. J. Mater. Chem. A 2011, 21, 13205-13212. 40. Gogotsi, Y.; Simon, P. True Performance Metrics in Electrochemical Energy Storage. Science 2011, 334, 917-918. 41. Yu, D. S.; Goh, K.; Wang, H.; Wei, L.; Jiang, W. C.; Zhang, Q.; Dai, L. M.; Chen, Y. Scalable Synthesis of Hierarchically Structured Carbon Nanotube-Graphene Fibres for Capacitive Energy Storage. Nat. Nanotechnol. 2014, 9, 555-562. 42. Yang, S. H.; Song, X. F.; Zhang, P.; Gao, L. A MnOOH/Nitrogen-Doped Graphene Hybrid Nanowires Sandwich Film for Flexible All-Solid-State Supercapacitors. J. Mater. Chem. A 2015, 3, 6136-6145. 43. Cheng, X. L.; Zhang, J.; Ren, J.; Liu, N.; Chen, P. N.; Zhang, Y.; Deng, J.; Wang, Y. G.; Peng, H. S. Design of a Hierarchical Ternary Hybrid for a Fiber-Shaped Asymmetric Supercapacitor with High Volumetric Energy Density. J. Phys. Chem. C 2016, 120, 9685-9691. 44. Zhai, S. L.; Jiang, W. C.; Wei, L.; Karahan, H. E.; Yuan, Y.; Ng, A. K.; Chen, Y. All-Carbon Solid-State Yarn Supercapacitors from Activated Carbon and Carbon Fibers for Smart Textiles. Mater. Horiz. 2015, 2, 598-605. 45. Jin, H. Y.; Zhou, L. M.; Mak, C. L.; Huang, H. T.; Tang, W. M.; Chan, H. L. W. High-Performance Fiber-Shaped Supercapacitors Using Carbon Fiber Thread (CFT)@Polyanilne and Functionalized CFT Electrodes for Wearable/Stretchable Eectronics. Nano Energy 2015, 11, 662-670. 46. Shen, B. S.; Guo, R. S.; Lang, J. W.; Liu, L.; Liu, L. Y.; Yan, X. B., A High-Temperature Flexible Supercapacitor Based on Pseudocapacitive Behavior of FeOOH in an Ionic Lquid Electrolyte. J. Mater. Chem. A 2016, 4, 8316-8327. 47. Pandey, G. P.; Hashmi, S. A. Performance of Solid-State Supercapacitors with Ionic

Liquid

1-Ethyl-3-Methylimidazolium

Tris(Pentafluoroethyl)

Trifluorophosphate Based Gel Polymer Electrolyte and Modified MWCNT Electrodes. Electrochim. Acta 2013, 105, 333-341. 48. Pandey, G. P.; Hashmi, S. A.; Kumar, Y. Performance Studies of Activated Charcoal Based Electrical Double Layer Capacitors with Ionic Liquid Gel



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Polymer Electrolytes. Energy Fuels 2010, 24, 6644-6652. 49. Pendashteh, A.; Palma, J.; Anderson M.; Marcilla R. Facile Synthesis of NiCoMnO4 Nanoparticles as Novel Electrode Materials for High-Performance Asymmetric Energy Storage Devices. J. Mater. Chem. A, 2015, 3, 16849-16859. 50. Zhang, F.; Lu, Y. H.; Yang, X.; Zhang, L.; Zhang, T. F.; Leng, K.; Wu, Y. P.; Huang, Y.; Ma, Y. F.; Chen, Y. S. A Flexible and High-Voltage Internal Tandem Supercapacitor Based on Graphene-Based Porous Materials with Ultrahigh Energy Density. Small 2014, 10, 2285-2292. 51. Yang, S. H.; Song, X. F.; Zhang, P.; Gao, L. Heating-Rate-Induced Porous alpha-Fe2O3 with Controllable Pore Size and Crystallinity Grown on Graphene for Supercapacitors. ACS Appl. Mater. Interfaces 2015, 7, 75-79. 52. Kim, T.; Jung, G.; Yoo, S.; Suh, K. S.; Ruoff, R. S. Activated Graphene-Based Carbons as Supercapacitor Electrodes with Macro- and Mesopores. ACS Nano 2013, 7, 6899-6905. 53. Zhou, G. M.; Wang, D. W.; Li, F.; Zhang, L. L.; Li, N.; Wu, Z. S.; Wen, L.; Lu, G. Q.; Cheng, H. M. Graphene-Wrapped Fe3O4 Anode Material with Improved Reversible Capacity and Cyclic Stability for Lithium Ion Batteries. Chem. Mater. 2010, 22, 5306-5313.


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Table of Contents Graphic


Recoverable Wire-Shaped Supercapacitors with Ultrahigh Volumetric

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