Highly porous polymer cryogel based tribopositive material for high performance triboelectric nanogenerators

The ongoing research for tribonegative materials has resulted in significant progress in triboelectric nanogenerators (TENG), but the search for tribopositive materials is limited. Therefore, it is still a challenging task to achieve low cost, readily available, easy process for fabrication of tribomaterials with high positive triboelectric properties for triboelectric nanogenerators. Here we propose a novel method to synthesize high porous cryogel films based on facile freezing, ultraviolet radiation and thawing processes and used it as the tribopositive material for TENG fabrication while spin-coated polydimethylsiloxane (PDMS) is used as the tribonegative material. The cryogel/PDMS TENG device with a dimension of 1 x 2 cm(2) showed an open circuit voltage of 170 V, and a short circuit current density of 17.1 mA/m(2) and an instantaneous power density of 2.95 W/m(2) which is able to light up 180 white LEDs directly. Thorough investigations divulged that the high output performance of TENG can be attributed to the porous structure of the cryogel films and the formation of high-density mechanoradicals associated with the porous structure, which was proved by using radical scavanger 2,2,6,6-tetramethyl-1-piperidinyloxy. This study provides a simple, cost-effective and easy way of preparing cryogel films as the tribopositive material for TENGs, which increases the portfolio of tribopositive materials used for triboelectric nanogenerator with prodigious prospects.