Direct electrospinning of reconstructable PVDF-TrFE nanofibrous mat onto conductive cement nanocomposite for triboelectricity-assisted net zero energy structure

As interest in harvesting green energy and utilizing renewable energy in the building sector has increased, the concept of Net Zero Energy Structure (NZES) has been highlighted. In this study, a strategy to develop the sustainable triboelectricity-assisted NZES is proposed. The multi-walled Carbon nanotube (MWCNT)-incorporated Cement Composite (CCC) is adopted as the structural/electrical member of the triboelectric nanogenerator (TENG) and the polyvinylidene difluoride-trifluoroethylene (PVDF-TrFE) nanofiber is directly electrospun onto the surface of CCC to act as the contact layer of the CCC-based TENG. The optimal concentration of incorporated MWCNT, C_MC, is determined to be 1 vol%, considering the compressive strength and electrical property of CCC. The conditions of the electrospinning process for configuring the electrospun PVDF-TrFE nanofibrous mat on the surfaces of CCCs with various shapes are investigated. The electrical output performance of the CCC-TENG is characterized by varying the various environmental and operational parameters. The direct electrospun PVDF-TrFE nanofibrous mat on the CCC-TENG significantly increases the output voltage to approximately 6 times that of flat TENG. The maximum peak power generated from CCC-TENG reaches 60.9 μW when the connected load resistance is 50 MΩ. Furthermore, as a proof-of-concept, the reconstructability of the PVDF-TrFE nanofibrous mat using the direct electrospinning process, as well as the restorations in terms of surface micro/nanostructures and electrical output performance, are demonstrated. Given the wide range of applications of cement and various functionalities of direct electrospinning technology, the sustainable triboelectricity-assisted NZES with CCC and direct electrospun PVDF-TrFE nanofibrous mat is expected to have great potential to take a step toward the development of sustainable Net Zero Energy Community in the future.