Enhancing Mechanical Energy Transfer of Piezoelectric Supercapacitors

Abstract

energy storage capabilities. A range of energy sources, including piezoelectric, pyroelectric, triboelectric, have been recently emphasized for energy harvesting from natural processes. [3][4][5][6] Typically, energy harvesting and storage systems can be integrated either extrinsically using electrical circuitries, or intrinsically via engineering the device structure with functionalized materials. [3,7] However, extrinsically integrated devices have high manufacturing cost due to the need of complex power management systems (rectifier), which reduces integration density. [8,9] Therefore, it is highly desirable to improve the integration level and minimize unnecessary energy loss in the external circuits between energy harvesting and storage devices.Recently, rectification free piezoelectric supercapacitors (PSCs) as an integrated device have been developed, which not only maintains the integration density of the devices but also provides continuous energy supply. The operation principle of PSC is based on the incorporation of piezoelectric materials in place of separators commonly used in supercapacitors and then harvesting the energy internally instead of relying on external power supply. In general, PSC is constructed using two electrodes, piezoelectric-separator and gel-electrolyte [10] where piezoelectric separator converts ubiquitously irregular and low-frequency mechanical vibration into electricity and simultaneously stores at the supercapacitive electrodes. Polyvinylidene fluoride (PVDF) film is commonly used in PSCs due to their excellent piezoelectric and mechanical properties. [11,12] The interfacial energy conversion efficiency of bare PVDF (electrically nonpolarized) in PSC, however, is poor and difficult to translate for real-time operation of electronic devices. [13] Among various approaches used to improve the performance, the PVDF matrix with fillers is an efficient and effective method. [13][14][15][16][17][18] For instance, Song et al. developed a rectification free, PVDF-based PSC. Simple carbon cloth was used as the electrode, with a gel electrolyte composed of PVA and H 2 SO 4 . The device achieved an aerial capacitance of 357.6 F m -2 , energy density of 0.049 mWh cm −2 and the power density 0.44 mW cm −2 . Kartiken et al. [19] embedded siloxene in to PVDF nanofibers to influence the structure and induce the β phase of PVDF, improving energy generation performance relative to bare PVDF. The fabricated device of the siloxene based supercapacitor achieved an areal capacitance of 28.98 mF cm -2The expected widespread use of wearable and other low-power healthcare devices has triggered great interest in piezoelectric materials as a promising energy harvester. However, traditional piezoelectric materials suffer from poor interfacial energy transfer when used in self-charging power cells. Herein, piezoelectric supercapacitors (PSCs) are engineered using MXene-incorporated polymeric piezo separator and MXene (Ti 3 C 2 T x ) multilayered sheets as electrodes. The MXene-blended polymer film showed ...

Enhanced Redox Cycle of Rod-Shaped MIL-88A/SnFe2O4@MXene Sheets for Fenton-like Degradation of Congo Red: Optimization and Mechanism

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Recent Advances and Strategies in MXene-Based Electrodes for Supercapacitors: Applications, Challenges and Future Prospects

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Development of Piezoelectric Elastomers and Their Applications in Soft Devices

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