Study On Printing Construction And Application Of Supercapacitor

As a key part of electrochemical energy storage device,supercapacitors have the characteristic of high power density,fast charge/discharge rate and attractive cycle stability.It is widely used in wearable devices,integrated systems,portable electronic devices and other fields.With the development of science and technology,people have higher demand for supercapacitors,especially providing more energy density in per unit area.Due to the low density of carbon-based materials,poor conductivity of transition metal oxides and the complex process of preparing high-loading electrodes.It is still a challenge to preparing supercapacitors with high areal energy density,remarkable rate capability and high integration.Herein,in this thesis we design advanced energy storage materials,printed electrodes device and fabricate supercapacitors with wearable devices to obtain high integration.The specific research contents are as follows:(1)Ti3C2/MXene and MF microspheres with opposite electronegativity were selfassembled by electrostatic interaction,which effectively prevents MXene nanosheets from restacking.MF microspheres not only provide a template for electrode materials,but also can be doped in situ due to the rich nitrogen elements,thus effectively improving the electrochemical of the materials.By exploring the rheological properties of MXene-N ink,we prepared suitable ink for printing.Constructed an electrode with adjustable area loading through printing technology and assembled a symmetrical supercapacitor.As a result,the derived symmetric supercapacitor exhibits a high areal and volumetric energy density of 0.42 mWh cm-2 and 0.83 mWh cm-3,respectively.(2)We demonstrate the in situ coupling of NiCoP bimetallic phosphide and Ti3C2/MXene to build up tunable mass loading electrodes throughout 3D printing technology.Thus printing electrodes possess robust open framework synergizes favorable capacitance of NiCoP and excellent conductivity of MXene.Accordingly,an asymmetric supercapacitor assembled with 3D-printed NCPM-CNT//AC-CNT,which augment the working voltage of the energy storage device.Then we evaluated the device which harvests remarkable areal and volumetric energy density of 0.89 mWh cm-2 and 2.2 mWh cm-3,outperforming the most of state-of-the-art carbon-based supercapacitors.The present work is anticipated to offer a viable solution toward the customized construction of multifunctional architectures via 3D printing for high-energy-density energy storage systems.(3)We report a self-powered wearable sensor device that is based upon designed vanadium nitride-graphene(VN-G)architectures.The preparations of VN-G have endowed it with both energy storage and sensing properties.Flexible quasi-solid-state VN-G supercapacitor with ultralight and binder-free features delivers a specific capacitance of～53 F g-1 with good cycle stability.On the other hand,VN-G derived pressure sensors fabricated throughout a spray-printing process also manifest favorably high sensitivity(40 kPa-1 at the range of 2-10 kPa),fast response time(～130 ms),perfect skin conformability,and outstanding stability under static and dynamic pressure conditions.In turn,their complementary unity into a selfpowered wearable sensor enables the precise detection of physiological motions ranging from pulse rate to phonetic recognition,holding promise for in-practical health monitoring applications.