Nanofiller modifications for boosting piezoelectric performance in lead-free polymer nanocomposites

Piezoelectric polymer nanocomposites have attracted substantial interest due to their capability to combine the excellent piezoelectric properties of ceramics with the flexibility of polymers. This combination makes them highly suitable for applications in portable and wearable sensors, as well as energy harvesters. However, their performance is often hindered by inconsistent local piezoelectricity, which results from uneven nanofiller distribution and ineffective stress transfer at the nanofiller/polymer interfaces. Addressing these challenges necessitates improving the dispersibility of nanofillers and enhancing interfacial interactions between nanofillers and the polymer matrix. Additionally, increasing and/or arranging spontaneous polarization in nanofillers can enhance the overall piezoelectricity of nanocomposites, mitigating performance declines. Recent studies aimed at improving the performance of lead-free piezoelectric polymer nanocomposites through nanofiller modifications such as surface coating/decoration and chemical doping have been summarized. The proposed modes of performance enhancement by surface-coated and chemically doped nanofillers have been introduced and summarized. Finally, some suggestions and strategies for future research endeavors are presented.