A review of structural connectivity in piezoelectric composites for high-performance nanogenerators

Piezoelectric composite-based nanogenerators are attracting attention as self-powered sources for next-generation wearable and portable electronic devices. The performance of piezoelectric composites is highly dependent on the connectivity structure. Conventional 0–3 type composites, in which piezoelectric fillers are randomly dispersed within a polymer matrix, suffer from reduced piezoelectric performance due to inefficient stress transfer. This review paper systematically investigates research that has enhanced piezoelectric performance by strategically designing the connectivity structure of piezoelectric composites. The correlation between various connectivity patterns, such as 1–3, 2–2, 3–1, and 3–3 types, and the piezoelectric output performance is analyzed. In particular, the three-dimensionally interconnected 3–3 structure has been demonstrated to be effective in improving output performance by facilitating continuous pathways for mechanical stress transfer. Additionally, fabrication strategies for designing these structures using various manufacturing techniques are discussed. In conclusion, this paper suggests the potential applicability of these high-performance composites in fields such as self-powered sensors, biomedical devices, and wearable electronics.