P(AA-MA)-PVA hydrogel-based triboelectric nanogenerator for energy harvesting and intelligent tennis stroke analysis

The development of self-powered sensors has drawn increasing interest as an effective strategy for real-time sports monitoring. Here, we propose a flexible polymer–polymer hydrogel-based triboelectric nanogenerator (PP-TENG) by integrating a P(AA-MA)-PVA hydrogel with PDMS encapsulation for biomechanical energy harvesting and tennis motion sensing. The hydrogel network simultaneously acts as a compliant electrode and triboelectric layer, while PDMS provides long-term protection and mechanical durability. Owing to its stretchability, adhesion, ionic conductivity, and self-healing capability, the PP-TENG exhibits excellent reliability under repeated excitations. The device achieves a peak open-circuit voltage of 182 V, a short-circuit current (ISC) of 23.2 μA, and a transferred charge of 91.4 nC, with a maximum output power of 3.3 mW at 4 MΩ. In addition to energy harvesting, the PP-TENG serves as a self-sustained sensor that enables real-time monitoring of diverse joint activities, including those of the neck, wrist, elbow, finger, ankle, and knee. In particular, for tennis applications, it enables real-time monitoring of bending angles and dynamic movements, offering potential in sports performance analysis, injury prevention, and wearable electronics.