Utilization of biomass wastes: coconut and Pangium edule shells as activated carbon for energy storage device materialDiah Susanti, Haniffudin Nurdiansah, Azzah Dyah Pramata, Tubagus Noor Rohmanuddin, Rindang Fajarin, Yeny Widya Rakhmawati, George Endri Kusuma and Fathan BahfieE3S Web Conf., 467 (2023) 04001DOI: https://doi.org/10.1051/e3sconf/202346704001