Self-Powering Gas Sensing System Enabled by Double-Layer Triboelectric Nanogenerators Based on Poly(2-vinylpyridine)@BaTiO3 Core–Shell Hybrids with Superior Dispersibility and Uniformity

Current core–shell hybrids used in diverse energy-related applications possess limited dispersibility and film uniformity that govern their overall performances. Herein, we showcase superdispersible core–shell hybrids (P2VP@BaTiO₃) composed of a poly(2-vinylpyridine) (P2VP) (5–20 wt %) and a barium titanate oxide (BaTiO3), maximizing dielectric constants by forming the high-quality uniform films. The P2VP@BaTiO₃-based triboelectric nanogenerators (TENGs), especially the 10 wt % P2VP (P2VP10@BaTiO₃)-based one, deliver significantly enhanced output performances compared to physically mixed P2VP/BaTiO₃ counterparts. The P2VP₁₀@BaTiO₃-based double-layer TENG exhibits not only an excellent transferred charge density of 281.7 μC m^–2 with a power density of 27.2 W m^–2 but also extraordinary device stability (∼100% sustainability of the maximum output voltage for 54,000 cycles and ∼68.7% voltage retention even at 99% humidity). Notably, introducing the MoS₂/SiO₂/Ni-mesh layer into this double-layer TENG enables ultrahigh charge density of up to 1228 μC m^–2, which is the top value reported for the TENGs so far. Furthermore, we also demonstrate a near-field communication-based sensing system for monitoring CO₂ gas using our developed self-powered generator with enhanced output performance and robustness.