Pulsed nanogenerator with huge instantaneous output power density.

A nanogenerator (NG) usually gives a high output voltage but low output current, so that the output power is low. In this paper, we developed a general approach that gives a hugely improved instantaneous output power of the NG, while the entire output energy stays the same. Our design is based on an off-on-off contact based switching during mechanical triggering that largely reduces the duration of the charging/discharge process, so that the instantaneous output current pulse is hugely improved without sacrificing the output voltage. For a vertical contact-separation mode triboelectric NG (TENG), the instantaneous output current and power peak can reach as high as 0.53 A and 142 W at a load of 500 Ω, respectively. The corresponding instantaneous output current and power density peak even approach 1325 A/m(2) and 3.6 × 10(5) W/m(2), which are more than 2500 and 1100 times higher than the previous records of TENG, respectively. For the rotation disk based TENG in the lateral sliding mode, the instantaneous output current and power density of 104 A/m(2) and 1.4 × 10(4) W/m(2) have been demonstrated at a frequency of 106.7 Hz. The approach presented here applies to both a piezoelectric NG and a triboelectric NG, and it is a major advance toward practical applications of a NG as a high pulsed power source.