Bioinspired elastic piezoelectric composites for high-performance mechanical energy harvesting

We report the sea sponge-inspired design and preparation of piezoelectric composite generators (PCGs) based on a three-dimensional electroceramic skeleton. The remarkable improvements in the piezopotential of the bioinspired structure have been theoretically analyzed using numerical simulations based on a phase-field simulation. The open-circuit voltage, short-circuit current density and instantaneous power density of the bioinspired PCG reach up to ∼25 V, ∼550 nA cm^-2 and ∼2.6 μW cm^-2, respectively, corresponding to about 16 times higher power than that of conventional particle based piezoelectric polymer composites. Moreover, the bioinspired PCG displays 30 times higher strain-voltage efficiency under stretching than the state-of-the-art performance of the flexible piezoelectric energy harvesters reported so far.