1.Introduction

As an important class of energy-storage devices,supercapacitors are attracting wide attention due to their fast charge and discharge rates,high power density,and long cycle lifetimes[1-10].Beside these remarkable advantages,supercapacitors also exhibit many other favorable attributes.It can be easily processed to construct flexible,stretchable or miniaturized con figurations,for ease of applications in portable and wearable electronics[11-19].Moreover,these unique con figurations facilitate their greater compatibility with various other functional devices.

The traditional single-function supercapacitor always appearing in a rigid bulky or planar format with large volume and structure limitation can no longer satisfy the development of next-generation electronics[20-30].And most of the state-of-the-art electronic devicesrely on the connection to external power supply through long wires,which often impede their mobile applications.Consequently,there is an urgent need to develop the unconventional multifunctional integrated supercapacitor.The integration strategy can endow the supercapacitors with multifunction as well as minimize the size of the electronic equipment[31-38].For example,people may come across the inconvenience of sudden power cut when using indoor electric appliances,and be bothered by carrying heavy batteries and power cords during a trip.Out of this consideration,some researchers come up with the ideal of constructing a wire-shaped device with an integrated current transmitting module and an incorporated supercapacitor.With such advanced “electric w ire”,when people are using their electric appliances,the cable can store the energy for later usage and provide the insurance for some delicate equipments by preventing them from being damaged during a sudden power cut.Some researchers introduced an ethanol detecting function to a supercapacitor,and the resultant ethanol sensor can achieve self-powering and detecting the concentration of ethanol in real time.The whole device is integrated tightly on one piece of flexible substrate,soit has enormous potential to be used as a wearable multifuntional device.

In this review,we summary the latest works in the field of integrated multifunctional supercapacitors.We describe the integration of the electrochemical energy storage with distinct functionalities such as photodectecting,electrochromism,activity monitoring,chemicals sensing,etc.The fabrication,characterization and performance of these diverse multifunctional supercapacitors are systemically discussed.Finally,w e propose the outlook of the future development of the multifunctional integrated supercapacitors.

2.Multifunctional integrated supercapacitors

2.1.Photodetector/supercapacitor integrated devices

Low-cost and fast response photodetectors are in great demand for various applications,such as security monitoring,environmental monitoring and space-to-space communication technologies,etc.[39-42].The conventional photodetector must work with external power supply,resulting in waste of additional space and energy.Integrating the photodetecting and energy storage function into one simplified and compact con figuration can make the device portable to meet the demand of lightweight electronics[43-52].

To incorporate the photodetecting function into supercapacitor,most researchers used the metallic oxide as the photosensitive material,while Zhang[53]used the Si nanowire(NW)to afford the electrode and the photocollector of a quick-charging and endurable integrated device.The device can run more than 10 h with once single charge in less than 100 s.Firstly,they grew the Si NW arrays on the silicon substrate vertically and orderly(Fig.1a)and coated part of the Si NWs with carbon,with another carbon-coated Si NW arrays to build the positive and negative electrodes( Figs.1b-d).The Si NWs without carbon coating served as the UV detector.Upon UV illumination,the photo-generated carriers would diffuse into the micro-supercapacitor,resulting in the increase of current in the circuit and the potential between the two electrodes( Figs.1e and f).Because of the UV detector consuming extremely low power and high specific surface area of Si NW array favorable to fast UV detection and high energy storage capacity as well,the device still show ed excellent endurance,even though the capacitance density was 13.6 F/cm 3.

(1)在含沙量≤3.0 kg/m3且滴灌带为一年用条件下，可采用新型泵前一级过滤与滴头抗堵新技术模式。在滴灌首部泵前安装低压旋转网式过滤器，过滤大颗粒泥沙与杂质。通过筛选出的适宜灌水器，将大部分细颗粒泥沙随滴头出水排入到田间。沉积在毛管内泥沙通过毛管尾端的辅助冲洗支管进行定时冲洗。该新技术模式改变了传统的泵后过滤器易堵塞、反冲洗频繁用水量大、压损较高的缺点。避免了因过滤而使黄河水中大量营养物质流失。运行管理维护费用低，占地面积较少，可大幅节约成本。

By a facile solvothermal method,Shen’s group fabricated a fiber-shaped asymmetric supercapacitor which was integrated with photodetecting function[54].They w rapped the graphenecoated carbon fibers around the Co3O4-coated titanium fibers which were immersed in the PVA-KOHgel solution before.Because of the over potential of reversible hydrogen electrosorption in a nanoporous carbon-based negative electrode,the operating potential window of the supercapacitor could be extended,which led to the enhancement of the as-assembled integrated system’s energy storage and power density.When the light was spread on the device,electron-hole pairs generated in graphene.Under the external field which was coming from the charged supercapacitor,electron-hole pairs separated and the current was generated.

Fig.1.Schematic of fabrication process and structure of the CNT/V2O5 NW based micro-supercapacitor integrated with a Sn O2 nanowires UV sensor.The illustration of Si NW array grow on the silicon substrate(a),selective coated carbon wall(b),the as-prepared multifunction supercapacitor(c),the charging circuit(d),the photodetecting process(e),and w orking mechanism(f).Copied with permission[53].Copyright 2015,Elsevier Ltd.

Ha’s group assembled a flexible all-solid-state planar-type micro-supercapacitor which can power the Sn O2 NW UV sensor that was integrated on the same flexible PET substrate[55].By a simple sol-gel method,they synthesized multi-walled carbon nanotube(MWCNT)/V2O5 NW composites as the electrodes.With PVA-LiCl electrolyte,the patterned micro-supercapacitor exhibited excellent electrochemical performance with a high volume capacitance of 80 F/cm 3 at a scan rate of 10 m V/s and excellent energy density of 6.8 m Wh/cm 3.After the irradiation of UV light,photocurrent through the Sn O2 NW sensor sharply increased,resulting in the enhancement of discharge rate of the microsupercapacitor.With the increase of the UV intensity from 0 to 1.4 m W/cm 2,the voltage drop rose from 6 m V/s to 18 m V/s,which show ed its potential application in the photodetecting area.

Xu used a conventional photolithography method to create the patterned graphene oxide(GO) film[56].Then the GO film was reduced to reduced graphene oxide(r GO)pattern and Au film was sprayed on the square electrodes to reinforce the conductivity.After several simple steps,the all-solid-state flexible r GO microsupercapacitor was obtained.By a chemical vapor deposition method,Cd S NWs were synthesized.The Cd S NWs were placed in gaps between the square electrodes to afford the photodetector part.The integrated device show ed excellent photosensitivity that the photoelectric response time and recover time are 0.83 s and 2.90 s,which was even quicker than that driven by external pow er source.

Watanabe assembled an all-solid-state carbon micro-supercapacitor by laser writing directly on polyimide(PI) filmsin Ar[57].Then they integrated this micro-supercapacitor with a UV photodetector based on Zn O nanoparticles with a small commercial solar panel on the same PI film to build an on-chip selfpow ered photodetection system.The micro-supercapacitor could be fully charged within 1 min and voltage remained above 0.55 V after 2 h.This on-chip integrated photodetection system exhibited a stable,distinct and fast response to the UV light illumination with a current on/off ratio of about 31.2 and the rise and decay times of 9.9 s and 15.9 s.

Niu’s team fabricated the foldable all-solid-state paper-like bifunctional integrated device with supercapacitor and photodetector functions based on single-walled carbon nanotube(SWCNT)films and TiO2 nanoparticles[58].What the device was quiet unique about was that it remained almost unchanged even folded by 180°.The sheet resistance of TiO2 nanoparticles-coated SWCNT film exhibited excellent stability at different folding levels.The speci fic capacitance and maximum power density can reach 28 F/g and 66.7 k W/kg.When the integrated device was exposed to the UV light with an intensity of 40 m W/cm 2,the photocurrent reached 2.77μA and sensitivity of 38.5 was achieved.

For the reason that ITO and FTO are fragile and expensive to produce and the sheet resistance is in the range of tens to hundreds of ohms per square which could cause the color change lagging behind the change of the stored energy under high current density.After several years of research,Lei’s group replace the ITO for the silver grids as the flexible transparent conductors,aiming to improve the electrochemical stability and flexibility of silver-based transparent electrode[74].They coated a layer of WO3 nanoparticles on the silver grid/PEDOT:PSS hybrid film to compose the flexible electrochromic device(Fig.3c).The advantages of using silver grid as substrate were improving the conductivity of the electrode and reducing the blooming effect distinctly.And the silver grid/PEDOT:PSS sheet show ed an outstanding performance with sheet resistance of 0.62Ω/sq at over 70%transparency.This hybrid device presented optical modulation of 81.9%at 633 nm,fast switching,and high coloration efficiency(124.5 cm 2/C)and an excellent electrochemical cycling stability(Fig.3d).

Wright reported new nanostructured Er-containing titania materials(Er@TiO2)which was made of a novel heterometallic Er(III)-doped polyoxotitanate cage[Ti8O7(OEt)21Er][73].Utilizing the Li+storage capacity and electrochromic propertiesof Er@TiO2,they sprayed the Er@TiO2 on the ITO glass to fabricate a bifunctional integrated electrochromic supercapacitor,which exhibited excellent electrochromic performances.At its rest state,the device was in yellow.The color turned dark gray when the device was charged above 1.3 V and bleached when it was discharged below 0.3 V.And the switching response time of coloring was 16.3 s and bleaching was 17.7 s.

The works mentioned above unify the photodetector and supercapacitor by the subtle design of architecture of electrode the hybridization of active materials.Although the devices showed excellent stability and fast response to the light,there are some improvement can be made in the later research,due to the limitation of photosensitive and the capacity short of the device.

2.2.Electrochromic supercapacitors

Electrochromic supercapacitor can be used not only for energystorage smart windows,which can adjust the lighting and heating of the building by charging the windows and changing its ow n color[19,61-65],but also for sensing variations of stored energy and being able to respond to the variations in a noticeable and predictable manner[66,67].Most of the planar electrochromic supercapacitors were built on the indium tin oxide(ITO)substrate just like Lee and Wright did[68],to meet the demand of wearable electronics,Lee[69],Mai[70]and Han[71]used the Ag NWs to made the flexible device.And the fiber construction was also put forward by Lin[72].

Chen made a hierarchically structured carbon micro fiber composed of an interconnected network of aligned SWCNTs and intercalated nitrogen-doped r GO sheets[60].The mesoporous construction endowed the material with a large specific surface area of 396 m2/g and excellent electrical conductivity of 102 S/cm.The composite fibers showed an ultrahigh specific volumetric capacity of 305 F/cm 3.The micro-supercapacitor was composed of PVA/H3PO4 gel electrolyte,without current collector,binder,separator or any other packaging materials,had a volumetric energy density of 6.3 m Wh/cm 3 while maintaining the 93% power density after 10000 cycles life(Fig.2a)and it retained more than 97%of its initial capacitance after bending 1000 times at 90°(Fig.2b).They assembled micro-supercapacitors in series and integrated the supercapacitor with a TiO2-based UV photodetector on a fluorine doped tin oxide(FTO)glass substrate(Fig.2c).The test show ed the photodetector had a steady response to ultraviolet light irradiation(Fig.2d).

In 2014,Lee designed a electrochromo-supercapacitor with the electrode that was composed of NiO nanoparticles uniformly grow n on the ITO substrate by a simple and low-cost solvothermal method[69].The NiO turned out to be appropriate electrode materials as chromo-supercapacitor.When the device was charged to 0.5 V,the color of the NiO film turned dark brow n(Fig.3a).After the electrical charge was completely consumed,the film returned to transparent.The device remained a transmittance modulation of 56.4%after 5000 cycles(Fig.3b)which may be due to the uniform nanoparticles morphology and stable chemical bonding of the NiO nanoparticle that benefited the charge transferring between the contact surfaces and within the electrode materials during the electrochemical process.

Zhi et al.synthesized h-WO3 through a microwave-assisted hydrothermal process and they found that h-WO3 based supercapacitors surprisingly show 17%enhanced performance under solar light[59].The wavelength dependence,capacitive mechanism,energy storage dynamics,and impedance analyses were put forward to investigate the enhancement mechanism.As an application of this finding,they built a self-powered photodetector-supercapacitor system based on h-WO3.The device’s voltagedrop rate was different between dark and illuminated conditions.The photoresponsivity increased from 0.11 to 0.16 as the light intensity increased from 40 m W/cm 2 to 100 m W/cm 2 and increased rapidly when the wavelength was less than 450 nm.Their work built the basis of later research on the h-WO3’s photosensitivity and opened a new gate to this field.

Fig.2.(a)The cycling stability of the micro-supercapacitor.The inset is the galvanostatic charge/discharge curve near 10,000 cycles.(b)Capacitance retention during 1,000 cycles at 90°bending angle.The inset is digital photo of a bent micro-supercapacitor.(c)Schematic of a self-powered photodetecting nanosystem.The inset is the SEM image of TiO2 nanorods array,and the scale bar is 1 mm.(d)Current response of the UV light.Copied with permission[60].Copyright 2014,Macmillan Publishers Limited.

Fig.3.(a)Transmittance spectra of the NiO nanoparticles film on ITO glass with seed layer under different voltage conditions,and the insets are the corresponding digital photos of the film.(b)Cycle performance of the NiO nanoparticles film measured in 1 mol/L KOH.Copied with permission[70].Copyright 2014,Elsevier Ltd.(c)Schematic description of the structure of the silver grid/PEDOT:PSS hybrid film.(d)Transmittance spectra of WO3 deposited on the pristine silver grid and the silver grid/PEDOT:PSS hybrid films under different voltage condition.Insets:The corresponding digital images of the electrodes.Copied with permission[71].Copyright 2015,WILEY-VCH Verlag GmbH&Co.KGaA,Weinheim.

Fig.4.(a)Schematic illustration of the fabrication of a flexible electrochromic supercapacitor electrode.(b)CV curves under normal and bent conditions at the scan rate of 100 m V/s,inset is digital photos of the supercapactor under the corresponding condition.(c)Transmittance spectra of the Ag NW/WO3 electrode measured under different voltage conditions,inset is corresponding digital images of the electrode.Copied with permission[72].Copyright 2016,The Royal Society of Chemistry.

The supercapacitor mentioned above can detect various kinds of physiological or mechanical movement such as pressure,Friction and stretch which is merely on one dimension direction.For this reason,we hoped the supercapacitor which can detect combination of complex move patterns can be brought out.

21世纪是天然气时代，该技术对于国内其他气区天然气回收具有借鉴意义，按照集团公司“十三五”规划，未来将在塔里木、鄂尔多斯、柴达、川渝等地区建成超过10×1010m3的大气区，天然气回收技术将会有巨大的应用前景。

Unlike conventional electrochromic systems making use of multilayer coatings on a glass substrate to adjust the light transmittance and control the temperature which cannot adapt its color according to the sunlight automatically.Han integrated the supercapacitor with a solar sensor to build a smart flexible electrochromic supercapacitor system[71].They sprayed the Ag NWs network on top of cellulose nanofiber based on paper substrate and deposited a thin layer of r GO layer on top of the Ag NWs serving as the supercapacitor active material and preventing from the air corrosion.Finally,they deposited WO3 nanoparticles uniformly on the electrode surface.Using ultrathin cellulose nanofiber paper as a substrate made the system showing exceptionally high transmittance of 99.1%.The as-prepared device exhibited a high coloration efficiency of 64.8 cm 2/C,specific capacitance of 406.0 F/g,energy density of 40.6-47.8 Wh/kg and power density of 6.8-16.9 k W/kg.The coloration efficiency of the device remained 75.0%after 10000 charge discharge cycles.

Different with previous works on the development of fibershaped devices focusing on either core-shell fibers or thread-like electronic devices,Lin prepared two parallel coil electrodes on a single fiber by a template method,using the poly(3,4-ethylenedioxythiophene)(PEDOT)deposited on the electrode surface as the active material[72].When the potential of 0.6 V was applied,the PEDOT coated on the cathode turned dark blue,while the anode show ed no change in color.When the bias potential was applied to an opposite direction,the PEDOT in dark blue returned to the natural gold color,while anther electrode turned to dark blue.The device reaction was so fast that coloring/bleaching time was less than 5 s.The single fiber device show ed several advantages over yarn and fabric,such as high integration ability.But its original gold color,compared to the mainstream transparent state,may limited its application.

文献[1]公开了一种传统的化学镍废水处理方法：在pH为10 ～ 12的条件下用双氧水氧化化学镀镍废水中的配位剂，镍离子将生成氢氧化镍沉淀，再以氧化钙沉淀废水中的磷酸根。该专利的发明者认为处理后的废水能够满足GB 21900-2008中“表3”的要求，但试验表明，对于含有柠檬酸的化学镀镍废水，这种处理方法只能满足“表2”的要求，即镍的质量浓度小于0.5 mg/L。

2.3.Physiological and mechanical activity monitor/supercapacitor integrated devices

The supercapacitor can also be integrated with the function to sense the physiological and mechanical activity.Since wearable electronics have attracted increasing attention along with the development of flexible and stretchable devices as well as the rapid spread of mobile equipment[43,75-79].Extended efforts on wearable electronics make it a promising platform to collect physiological and mechanical information from the human body[80-86].Integrating the supercapacitor with the activity-monitoring function can ensure its application in medical diagnosis and treatment,wellness preventive care and sports game.

Most flexible planar electrochromic supercapacitors are built on the silver grid or NWs coated PET substrates as the current collector,which can better suits the demands of wearable devices than the counterpart built on the ITO or FTO.And the flexible fiber electrochromic supercapacitors are also brought out to meet the weavability.

Kim presented a wearable energy storage device,composed of triboelectric generators(TEGs)integrated with supercapacitors,which can be applied either as an activity monitor or as power source for wearable sensors[87].Since all parts were fabricated on a conductive carbon fabric,they could be w oven onto any location people desired of the conventional cloth,and interconnected with each other by conductive threads.The structure and working,mechanism of the wearable energy storage system are exhibited schematically in Figs.5a and b.The TEGs were placed in the armpit area to collect friction,whereas the supercapacitor was located on the chest section that is free from friction and other external force,and still close to the TEGs.The current generated during walking and storage was also shown in Fig.5c.The design of the TEGs was based on four parallel TEGS,which allow ed them to utilize both the vertical and horizontal friction generated between the arm and the torso.The most novel design of this device was that unlike TEGs developed before,it allow ed TEGs to generate Electricity without the need for air gaps.And it can generated electricity through both horizontal and vertical friction,with an average output power density of 0.18μW/cm 2 at 1.5 Hz under typical activity of running.

Fig.5.(a)Schematic description of arm swings with TEG and supercapacitor equipped.(b)Circuit diagram of the integrated TEG and supercapacitor.(c)Illustration of the human activity sensor.The generated electricity was recorded during the stretching,w alk,running,sprint,and w alk again.Copied with permission[87].Copyright 2014,WILEY-VCH Verlag GmbH&Co.KGaA,Weinheim.

Fan et al.introduced a flexible,lightweight,hierarchical porous Mn3O4/graphite foams electrode[88].Hierarchical porous structure offered the flexible supercapacitors outstanding properties,including high specific surface area,low areal mass density and high electric conductivity.The Mn3O4/graphite foams could be facilely integrated as both liquid-state and solid-state supercapacitor electrodes without additives or bindings.The specific capacitance of 538 F/g and an optimal overall capacitance of 260 F/g based on the pure Mn3O4 have been achieved.The multilevel porous graphite foam show ed excellent electrical stability with the capacitance retention of 90%after 10000 cycles at 10 A/g.They integrated the supercapacitor with a wearable ultrasensitive strain sensor(Fig.6a),and the integrated flexible device could power itself, fit into human skins,and accurately detect both coarse and steady motions.For example,when attached to a finger(Fig.6b),the device show ed unstable electric signals as the finger bent.When attached to skins w here the carotid artery is(Fig.6c),periodic electric signals are collected,giving the information that the heart beating rate was 96 per minute.

Pan’s team presented an electrospun ionic fabric utilizing nanofibrous structures with an extraordinarily high pressure-tocapacitance sensitivity of 114 n F/k Pa with resolution of 2.4 Pa and mechanical response time of 4.2 ms,which was at least 1,000 times higher than any existing capacitive sensors[89].Under the external pressure,the nanofibrous layer and the conductive fabric was compressed and charged ionic was increasing.And the change of the contact area would lead to a variation in interfacial capacitance.In this way,the pressure applied on the device can be detected.And the device was noise proof and exhibited excellent signal stability for wearable applications.

(1)盐酸法适用于攀枝花钛铁矿生产人造金红石工艺路线，但目前面临着攀枝花钛铁矿粒度过细且越来越细化的问题，而且人造金红石中CaO、SiO2等杂质元素高于氯化钛白对原料的要求。

Maiinvented a flexible electrochromic supercapacitor electrode based on the flexible transparent conducting silver nanowire(Ag NW)substrates as well and active material WO3 film[70](Fig.4a).The device was stable under different bending conditions(Fig.4b).The color changed between dark blue and transparent as the pseudocapacitive reactions happened:WO3+xe-+x H+↔Hx WO3.When-0.5 V was applied on the Ag NW/WO3 electrode,the supercapacitor changed to dark blue with an optical transparency of 11.8%(Fig.4c).This electrode exhibited high coloration efficiency up to 80.2 cm 2/C,fast response speed(coloring in 1.7 s and bleaching in 1.0 s)and outstanding stability(remained 72.6%of the initial capacitance at a scan rate of 100 m V/s after 5000 cycles).

Fig.6.(a)Schematic description of the flexible all-solid-state supercapacitor integrated with a strain sensor.(b)Real-time detection of finger bending.(c)Realtime detection of carotid artery pulses in real time,inset:digital image of the integrated device(left)and the application in pulse test(right).Copied with permission[88].Copyright 2017,WILEY-VCH Verlag GmbH&Co.KGaA,Weinheim.

2.4.Other multifunctional integrated supercapacitors

2.4.1.Chemical sensor/supercapacitor integrated devices

Instead of the photodetecting and physiological mechanical activity detecting function,the supercapacitor can also be integrated with the chemical sensor.The pollution of air and water has become a major problem that all people are concerned about.The detection of the chemical plays a vital role in preventing people from chemical pollutions.And the chemical sensors can be applied to detect the concentration of certain kind of chemcial and help people to control the taking in of this chemical[90,91].The supercapacitor integrated with chemical sensor can work continuously without external power,which suits the development direction of future chemical sensor.

Zhen’s group connected micro-supercapacitor arrays to afford the power resource for a wearable ethanol sensor on the same PET substrate[92](Fig.7a).The voltage of the micro-supercapacitor arrays was calibrated by voltage regulate device,making the output voltage stable at 0.8 V.When the sensor was exposed to the C2H5OH gas,the C2H5OH and O2 reacted and produced CO2,H2O and a large number of electronics on the MWCNTs/PANI composite layer(Fig.7b).The electron-hole connection and the reduction of PANI caused the resistance of the active layers increasing,leading to the decrease of current and the increase of tandem resistor.The device built accurate selectivity to the ethanol among the other gas such as methanol,dimethyl formamide,acetone,etc.(Fig.7c).And the as-prepared system was quite stable under different bending station(Fig.7d).The signal was further collected and settled by the CPU and alarmed the user(Fig.7e).

Other than the detecting function mentioned above,the supercapacitors can achieve the energy storage and transmission meantime.Cable-shaped supercapacitors are welcome for its attractive properties such as small size,lightweight,and bendability[93].Combining the supercapacitor’s intrinsic capability to store energy with the electricity transmittance function can alleviate energy distribution and guarantee the electricity supply after cutting off the power,liberating people from the heavy energy supply system[94].Therefore the integrated electrical cable/supercapacitors could provide potential applications in energy storage and electronics.

2.4.2.Integrated electrical cable/supecapacitors

（1）计划。针对临床免疫检验过程进行整体规划，制定工作方案，从管控规划到人员培训，从检验样本获取到检验结果分析，针对免疫检验流程及管理制度，严格按照《临床免疫检验细则》进行科学训练、专业知识学习以及消毒意识，设置新的临床免疫消毒标准、洗手点以及检验功能区域划分[1] 。

登录模块为游客登录APP操作。注册模块是游客注册为会员操作，注册功能和注销功能紧密相连，注销和注册都可以由管理员进行。而注册还可以由游客自行完成。下棋模块是APP的核心模块，通过本模块进行中国象棋游戏，游戏结束后可进行再来一局和返回菜单功能。

实测泵排量和工具压降之间的关系如图6所示。工具的压降和泵排量之间成类似二次曲线的关系，其压降随着泵排量的增大而逐渐增大。

Fig.7.(a)Schematic of the micro-supercapacitor based on PPy film.(b)Schematic of the as-fabricated ethanol gas sensor part.(c)Sensitivity test towards different gas of the device.(d)The potential under different bent level.(e)Drawing of a user using the alcohol detecting integrated system while driving.Copied with permission[92].Copyright 2017,Elsevier Ltd.

Thomas grow Fe2O3@C nanorods uniformly on strand of carbon fiber and coated the cooper w ire with Cu O nanowhiskers to afford the anode and cathode of the coil-type asymmetric supercapacitor electrical cable[95].Compared to symmetric supercapacitor,the as-prepared device has broader cell operation voltage.And the device show ed extraordinary mechanical and electrochemical stability,extraordinary rate capability(95.4%),high energy density(0.85 m Wh/cm 3),remarkable flexibility and bendability,and superior bending cycle stability(Capacitance retention remained 94%after 4000 cycles at different bending states).The superb electrical performance can be attributed to the novel nanostructure design in both anodes and cathodes.

Wang fabricated a juglone/PPy composite-based fiber electrode by a facile galvanostatic polymerization method[96].They then connected these wire-shaped electrodes with the metal cores on the two side of a conventional electrical wire to form an integrated electrical cable/supercapacitor.When this integrated electrical cable/supercapacitor was used in practical application,it constituted a classical parallel resistor-capacitor circuit along with the external electric appliance.With this integrated electrical cable/supercapacitor,the bulk can be lighted with the power supply and stay bright even after the power was cut off( Figs.8a-d).Compared to the traditional cable’s voltage suddenly dropping after cutting out the power,the counterpart of integrated cable could significantly retain a high voltage for a long time( Figs.8e and f).Both circuit analysis and display demonstration testified that the integrated electrical cable/supercapacitor acted as a conductive wire to conduct the electricity and a supercapacitor to store the energy simultaneously.Using this integrated cable/supercapacitor to replace conventional electrical wires,the energy distribution and supply applications might be revolutionized,because energy generated by various physical or chemical sources can be distributed to users directly with no need of additional energy storage equipment.

通过查阅资料，并筛选整理数据选取云南地区2000年～2010年5级以上的17次地震为样本数据，原始数据[4～8]如表1所示。

Fig.8.Schematic of the bulbs powered by(a)a conventional electric wire and(b)an as-fabricated flexible integrated electrical cable.(c,d)Demonstration of the bifunctional integrated cable can light the LED after removing the power.Variations of the voltage across the bulbs after cutting off the power with conventional electric w ires(e)and this integrated electrical cables(f)used as connections,respectively.Insets in e and f are the corresponding circuit schematics.Copied with permission[96].Copyright 2016,WILEY-VCH Verlag GmbH&Co.KGaA,Weinheim.

And there are some other function integrated with the capacitor,such as Liu integrated the Sn O2-based memristor with supercapacitor to stabilize the voltage of supercapacitor[97].Fan integrated solar hydrogen generation function with supercapacitor[98].

区域供水与需水的动态过程受到多方面因素影响，主要包括两类：一方面，气温、降水等自然水循环要素使供需态势受到影响；另一方面，经济社会发展增加用水需求，加大供水系统压力。通常由于降水偏少、天气干燥、蒸发量增大而发生气象干旱。

3.Conclusions and outlook

With the rapid development of portable,wearable and smart electronics,there is an urgent need for a breaking through development of the traditional single-function supercapacitor with sole energy supply ability.Integration approaches can endow the supercapacitor with multiple functionalities,e.g.,photodetecting,electrochromism,activity monitoring,chemicals sensing,etc.In this review,we conclude the recent progress in the field of integrated multifunctional supercapacitor.We highlight the delicate design which brought several distinct functions into one device.And these kinds of devices make it possible for the development of flexible,wearable,portable,lightweight electronics.

但美国战略界大多数学者，显然不是以这种方式看待“南海核心利益说”。他们认为，“南海核心利益说”首先是个极富现实性的理论问题，外交政策表述层面的讨论属于艺术性范畴，不是他们关注的核心。

Due to the urgent need for the unconventional multifunction supercapacitors,various kinds of integrated systems are emerging rapidly.Despite the success in proof-of-concept demonstrations,further improvement needs to be carried out before practical applications of these lab-scale integrated devices.In particular,the capacitance of these integrated supercapacitors is mostly low,and still cannot support durable usage of electronics.And the accuracy and detection limitation of these sensors or detectors still have some room to enhance.In order to meet the demand of the practical application,the method to produce the multifunctional supercapacitors facilely on large scale should be brought out.

Besides these unconventional integrated multifunctional supercapacitors discussed in the review,more integration device which can detect the mechanical activity,humidity,sound and chemical compound could be figured out.Detecting mechanical activity could be applied on the man-machine interaction.Detecting humidity can facilitate supervising the condition and environment of manufacture process.Detecting sound can be used to monitor the noise level.Detecting chemical compound could play a vital role in the petrochemical Engineering and prevent people from the chemical poison.Additionally,more than two kinds of function can be integrated into one device to minimize the volume and promote the development of portable and wearable electronics.

Acknowledgments

The authors acknowledge the financial support of the National Natural Science Foundation of China(No.51502009)and the Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle(No.ST201522008).

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