**5.3 Applications of nanocrystal of naturally occurring materials**

Due to the growing environmental concerns, it has indeed been emphasized that natural fibers have many advantages over synthetics because of their eco-friendly nature. However, when we use natural fibers, we cannot get more stiffness than synthetic fibers. Cellulose nanocrystals have been used as structural and geometric models of "cellulose" in various functional products. In addition, the active incorporation of electroluminescent compounds in naturally found nanocomposites results in a lower coefficient of thermal expansion. To prevent ionic diffusivity, cellulose whiskers (less than 10%) can be applied to low-density electrolyte polymers that are used in lithium-ion batteries.
