fig1

Figure 1. Schematic of TENG-powered battery charging. Mechanical energy is converted into a pulsed electrical output, which passes through a rectifier, capacitor, and optional DC-DC converter before charging a battery. Energy losses occur during rectification, capacitor leakage, and impedance mismatch, reducing overall charging efficiency. The stored energy can power low-power electronics, while reproducibility and battery degradation remain key challenges. TENG: Triboelectric nanogenerator; DC-DC: direct current to direct current converter; LED: light-emitting diode; MCU: microcontroller unit; ESR: equivalent series resistance.