A High Efficacy Self‐Charging MoSe₂ Solid‐State Supercapacitor Using Electrospun Nanofibrous Piezoelectric Separator with Ionogel Electrolyte

Abstract

compartments, namely, (i) energy harvesting and (ii) energy storage in which the former generates the energy while the latter is used to store the generated energy. [6,7] Renewable energy sources such as solar, wind, hydropower, mechanical energy (piezoelectric/triboelectric nanogenerator), and electrochemical energy (fuel cells) are used as energy harvesting system, whereas batteries and supercapacitors are used as energy storing system in the design of selfcharging power system. [8][9][10][11][12] Renewable power source based self-charging power system such as coupling of the solar cell/ photovoltaics with the electrochemical energy storage are commercialized for making use of the photon energy into useful energy. [13,14] Hitherto, the utilization of biomechanical energy for the selfcharging system is still in research level, and further efforts are needed to be undertaken for practical applications. The concept of self-charging and/or self-powered system for harvesting and storing mechanical and/or biomechanical energy becomes plausible after the research findings of Wang and co-workers for the first time when they designed a self-powered system using nanogenerator (NG) and supercapacitor in 2012. [2] Up to date two different types of self-charging power cells have been reported such as (i) external powering and (ii) internally integrating the system. [8,[15][16][17] In the former case, the mechanical energy harvester is externally connected to the energy storage device using a rectifier, whereas the latter uses an all-in-one integrated system which will be beneficial for several applications in portable and wearable devices due to their miniaturized size. [18,19] The pulsating alternating current output of nanogenerator is the major concern for the practical application of NG based self-charging power cells (SCPCs) due to their low energy conversion efficiency. [7,20] Therefore, the design and development of high-performance self-charging power cell with high energy conversion efficiency are highly essential. In this scenario, integrated self-charging supercapacitor power cell (SCSPC) utilizing supercapacitor as energy storage device attracts much attention compared to batteries mainly due to the fast charging rates of a capacitive type electrode; it can scavenge/store the piezo-electrochemically generated Self-charging supercapacitor power cell (SCSPC) received much attention for harvesting and storing energy in an integrated device, which paves the way for developing maintenance free autonomous power systems for various electronic devices. In this work, a new type of SCSPC device is fabricated comprising 2D molybdenum di-selenide (MoSe 2 ) as an energy storing electrode with polyvinylidene fluoride-co-hexafluoropropylene/ tetraethylammonium tetrafluoroborate (PVDF-co-HFP/TEABF 4 ) ion gelled polyvinylidene fluoride/sodium niobate (PVDF/NaNbO 3 ) as the piezopolymer electrolyte. The fabricated SCSPC delivers a specific capacitance of 18.93 mF cm −2 with a specific energy of 37.90 mJ cm −2 at a specific power...

Free-Standing PVDF/Reduced Graphene Oxide Film for All-Solid-State Flexible Supercapacitors towards Self-Powered Systems

“…Figure S3 shows the comparative voltage output of the PVDF and electrospun PVDF/sodium niobate nanofibrous mat obtained under an applied compressive force of 10 N. The incorporation of sodium niobate in the PVDF matrix results in an output voltage of 25 V, which is higher compared to bare PVDF, thus indicating the enhanced piezoelectric response. The improved energy harvesting properties of the PVDF/sodium niobate is due to the enhancement in dipole alignments of PVDF and the synergetic effect of the piezoelectric ceramics [13,31]. The voltage output of the fabricated device under various compressive forces (10 to 40 N) is shown in Figure 2A-D.…”

“…A facile and low-cost electrospinning technique was adopted for the preparation of composite PVDF/sodium niobate nanofibers. Briefly, the PVDF polymer solution was prepared as per the literature [13]. At first, 10 wt % of PVDF was dissolved in acetone and N,N-dimethylacetamide in the ratio of 70:30 (V/V), then further ultra-sonicated to form the transparent polymer solution.…”

“…The major advantages of these polymer composite films are ease of synthesis, lightweight, flexible, and corrosion resistance [11]. The main benefits of the composite film over the pure polymer is the enhancement in the electrical, mechanical and tensile properties of the polymer composites [12,13]. The enhancement in the properties of the composite film is mainly due to the interaction between the filler materials and the carbon chain groups in the polymer matrix [14,15].…”

Nanogenerator-Based Self-Charging Energy Storage Devices

“…Reprinted with permission from Ref. [21] of 30 N within 100 s [37]. By comparison, it is observed that the MoSe 2 SCSPC device has better self-charging performance than the devices depicted in Figs.…”

In Situ Monitoring Small Energy Storage Change of Electrochromic Supercapacitors via Perovskite Photodetectors

“…Several renewable energy including sunlight, wind, heat, tide, or mechanical force with the main drawback of instability demands strong and stable energy storage devices to match with . This urgently pushes the advancement of the integral system . Among different kinds of energy storage devices, supercapacitors (SCs) are one of the most suitable one for cooperating with other kinds of devices into a system due to the advantage of fast charging ability and long‐term stability.…”