# Electrospun Nanomaterials for Energy Applications: Recent Advances
## 11 Conclusions  
Electrospinning is a very simple, widely accessible, scalable, and cost-effective technique, particularly suitable for the manufacturing of engineered fibrous nanomaterials on an industrial scale. In fact, different from the other synthetic techniques, the production process via electrospinning can proceed _continuously_, by collecting the as-spun fibers on a suitably designed system using rotating drums. Any thermal treatment needed to modify the fiber physicochemical properties can be operated _separately_, with no necessity of interrupting the production process. Obviously, this constitutes a _singular_ inherent advantage in view of the large-scale production. Besides, in an industrial context, multi-needle and needleless systems allow facing up to the moderate productivity of the conventional electrospinning. The outstanding physical and chemical properties of the large variety of intriguing nanostructured materials produced via this fascinating synthetic approach are suitable to the development of a huge number of advanced applications involving the most different fields, exhaustively illustrated in several excellent reviews. The focus of this review is on energy-related applications of the electrospun nanomaterials. In particular, the recent advances produced by their use in secondary alkali metal-ion batteries, redox flow batteries, metal-air batteries, supercapacitors, reactors for water desalination via capacitive deionization, hydrogen production by solar-driven water splitting, nanogenerators for energy harvesting, and textiles for energy-saving personal thermal management are reviewed, trying to report aspects believed to be of importance to attract the interest and stimulate the inventiveness of the readers. Even if outstanding results have been achieved, many are the challenges still to be faced, bearing in mind the ultimate goal of pushing electrospun nanomaterials from the laboratory to industry. For instance, although doping with aliovalent elements has enhanced their conductive properties, the mechanical strength of ceramic nanofibers needs to be improved, and solutions for the production of flexible mats for their use as free-standing electrodes have still to be found. In the case of carbonaceous fibrous membranes, despite the progress recently made, the tendency towards the aggregation of the dispersed very small-sized nanoparticles responsible for the electrode instability still needs attention. Besides, the lack of full control of their pore size and distribution hinders from having carbon fibers with finely tunable porosity and hierarchical porosity, thus limiting the performance of all applications benefiting from them. A similar necessity concerns fiber diameter and mechanical robustness, as well as orientation. Another absolutely non-negligible aspect is represented by the impact on human health and the environment. The solvent (\(N\),\(N\)-dimethylformamide) utilized to disperse the polymers (polyacrylamideonitrile and polyvinyl pyrrolone) most frequently selected for the fabrication of carbon-, carbon-based, and ceramic fibers are not free of toxic effects. In light of these considerations, some future research directions in the field of energy-related applications of electrospun nanomaterials could be:  
* Search for safer polymer/solvent combinations and abundant, non-toxic precursors to limit the impact of the fiber production on human health as well as the environment. * Development of ceramic fibers with improved mechanical strength for the production of flexible mats to be used as free-standing electrodes. * For the composite fibers, improvement of the existing approaches to contrast the tendency towards the aggregation of the very small-sized nanoparticles embedded into the carbon matrix. * Search for new additives and development of new fiber surface-modification methods to generate electrospun nanomaterials endowed with new functionalities.