Highly stretchable lactate-based piezoelectric elastomer with high current density and fast self-healing behaviors

Piezoelectric generators (PEGs) represent an attractive energy harvesting option for applications such as self-powered wearable electronics and implantable devices. However, PEG implementations in these scenarios suffer from low current density. The traditional solution is to enhance the piezoelectric coefficient by manipulating the dipole orientation of the piezoelectric material. To provide an alternative, we present a new PEG concept with a lactate-based piezoelectric elastomer (LBPE) by introducing flexible chain segments into lactate, which is responsible for piezoelectricity. The generated current density increased significantly because of the reduced modulus of elasticity. We observed a maximum strain capacity of 4.39 and a stable resilience after 500 stretching cycles. The promising mechanical properties of LBPE include a high piezoelectric response with a peak open-circuit voltage density of 0.24 V cm−2, and a corresponding short-circuit current density of 19.75 μA cm−2, which is 4.21 times that of poly(vinylidene fluoride–trifluoroethylene)-based PEG. Owing to its low glass-transition temperature and linear molecular chain nature, LBPE exhibits fast self-healing within 15 min at body temperature. It retained 77.38% and 44.98% of the initial electrical and mechanical property values, respectively, after five cut-heal cycles.