## 6 Melt Electrospun Nanocomposites
Poly (vinylidene fluoride) (PVDF) is one of the suitable polymers in the application of lithium-ion separators and gives the opportunity to replace polyolefin systems because of its good electrolyte affinity, excellent thermal stability and desired electrochemical performance [147]. The electrospinningning technique can provide nanofibrous membranes with a controllable fiber diameter and high porosity for lithium-ion battery separators, improving the lithium-ion conductivity, electrolyte absorption, and retention rate [148]. Coating of separators with ceramic layers like SiO\({}_{2}\), Al\({}_{2}\)O\({}_{3}\), ZrO\({}_{2}\), TiO\({}_{2}\), and CeO\({}_{2}\), were found to be an effective and economical way to improve the thermal stability and wettability of the separator [149]. Sputtering of the mentioned ceramic particles into melt electrospun three-dimensional PVDF networks, with a smooth surface and a diameter of 3.2 \(\upmu\)m, boosted the ion conductivity to 2.055 mS/cm at room temperature--much higher than that of the commercial PE separator. In addition, an improvement in discharge capacity to 161.5 mA.h/g and a retention rate of 84.3% after 100 cycles were reported. This ceramic nanoparticle-coated melt-electrospun PVDF is a promising separator for a high-power and more secure lithium-ion battery using a cost effective and eco-friendly process. Nanomaterials containing TiO\({}_{2}\) have been found to be effective in removal of dyes from wastewater, which draws a lot of attention as it minimizes the threat for human health [150]. Typical dye-removing methods include chemical and physical methods, such as chemical coagulation and flocculation, precipitation, and ozonation [151]. Since titanium nanoparticles are potential materials for decolorization of textile dye effluents, the preparation of a TiO\({}_{2}\)-functionalized polymeric fabric would be an efficient way to improve dye-wastewater decolorization [152]. Mel electrospinningning was applied in the preparation of PP fibers containing TiO\({}_{2}\) nanoparticles for a photocatalytic application. Prior to electrospinningning, titanium nanoparticles and sodium stearate were added into PP to boost the electrical conductivity of the polymer melt and improve the electrospinningning process. Optimized process conditions (applied voltage, tip-to-collector distance, and flow rate) provided melt electrospun fibers of pure PP and PP/TiO\({}_{2}\) nanocomposite with an average diameter of 700 and 800 nm, respectively. With a 90% of decolorization efficiency, this melt electrospun nanocomposite fabric can be considered as a suitable filter with a good photocatalytic activity. Silica (SiO\({}_{2}\)) nanoparticles are amongst the most widely used inorganic materials due to their mild reactivity and good chemical properties. Adding SiO\({}_{2}\) nanoparticles in a polymer like PET would provide a nanocomposite fiber with good thermal and chemical stability, excellent mechanical properties, and well dye ability [153]. Nano- and microfibers of PET/SiO\({}_{2}\)-nanocomposite were successfully prepared by laser melt electrospinning with a fiber diameter range between 500 nm and 7 \(\upmu\)m [154]. Laser current and applied voltage significantly changed the morphology of the fiber. At high voltage and low current, spray-like particles and ultrafine fibers could be fabricated. Nanocomposite fibers based on poly-L-lactic acid (PLLA) and nHAp [59] have also been obtained by melt electrospinningning. PLLA containing HAp has been widely used in biomedical application thanks to the its biocompatibility and osteoconductivity, and also because it improves some properties of the polymer [155]. Uniform fibers were obtained, and specifically the addition of a 3 wt.% of nHAp resulted in a decrease of the fiber diameter from 7.1 \(\upmu\)m to 4.5 \(\upmu\)m, but with a change from smooth to a rough surface. The hydrophilicity of the mats was also enhanced to a certain extent due to the hydrophilic nature and ionic affinity of nHAp particles.