¹ Department of Chemical Engineering, AC Tech Campus, Anna University, Chennai, India;
² Department of Physics, The Gandhigram Rural Institute, Chinnalapatti, Dindigul District, India;
³ Department of Chemical Engineering, Sri Venkateswara College of Engineering, Sriperumbudur, Kancheepuram, India;
⁴ Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia;
⁵ Department of Food Science and Biotechnology, Sejong University, Seoul 05006, South Korea.
* Correspondence: jrajabathar@ksu.edu.sa

With the concept of Waste-to-Energy our team has developed a more-promising composite separator material for battery applications. Zinc-based porous co-ordination polymeric crystals (CALF-20) were made to grow on the surface of cellulose-based substrate, residual cotton (Gossypium herbaceum). These CALF-20 crystals were produced in a greener approach utilizing the aqueous solvent caustic potash (i.e. mother liquor). The compatibility behaviour between CALF-20 crystals and cotton was enhanced by the addition of surface modifier dopamine. The results of the scanning electron microscopy (SEM) were excellent, and it revealed the good adherence characteristics developed between CALF-20 crystals and the cotton. The sharp crystalline peak at 2θ = 22.36° in 002 plane of X-ray diffraction (XRD) spectra proved the strong bonding of hydroxyl molecules onto the cotton surface. The Brunauer-Emmett-Teller (BET) surface area was calculated to be 23.98 m2/g and the isotherms obtained demonstrated the existence of both microporous and mesoporous structural characteristics. The charge transfer resistance (Rct) is found to be low with high ionic conductivity. From the above-mentioned results, it is highly positive that our composite could serve its purpose as separator in batteries.