Material types and metabolic categories in representative piezo-electrotrophy studies. The references related to piezoelectric materials in the image include struvite [37], BaTiO₃ [1], PVDF [35], and diphenylalanine [36]. The references related to metabolic processes in the image include carbon fixation [1,38], sulfur Reduction [1], organic degradation [1], cell growth [1], metal reduction, and denitrification [1,37].