Giyanto, Jon Affi, Gunawarman, Murni Handayani, and Yuli Yetri. 2026. “Utilization of Coconut Shells As a Source of Graphene Nanosheets Fe N-GNS for Environmentally Friendly Primary Battery Electrodes”. Piston: Journal of Technical Engineering 9 (2):85-89. https://openjournal.unpam.ac.id/index.php/Piston/article/view/57488.