The development of lead-free high performing novel piezoelectric materials could allow for lightweight and non-toxic piezoelectric energy harvesters. Herein, is disclosed novel organic-inorganic hybrid metalates (OIHM) incorporating histammonium salts of HistammoniumMXn, with M being a metal and X being a halide. Composites with non-reactive polymer composites such as polyvinylidene difluoride (PVDF) displayed exhibit excellent flexibility and promising unpoled piezoelectric coefficients.