Interfacial modification boosted permittivity and triboelectric performance of liquid doping composites for high-performance flexible triboelectric nanogenerators

Composites' interface is the contact area between filler and matrix, which is a critical issue in composites' permittivity and thereby of great value to improve friction composites' performance in triboelectric nanogenerators (TENGs). However, composites' interfacial influence on triboelectric performance was not clear in past years even numerous composites were prepared, which limited materials' advance of triboelectric performance. Here, a systematic investigation about the composites' interfacial influence was performed on liquid doping polydimethylsiloxane (PDMS) composites, in which interfacial area and compatibility were found with great importance to composites' permittivity and triboelectric performance. Through high preparation stirring speed and appropriate surfactant additive, interfacial modification of enlarging interfacial area and compatible interface was facilely achieved. The as-prepared composites' permittivity and triboelectric performance were remarkably promoted as compared to composites without interfacial modification, achieving 8.1-fold in output voltage and 9.5-fold in output current of pristine PDMS. Further, the composites were applied to assemble TENG for energy harvesting and movement detection. This work revealed the interface properties’ influence on composites permittivity and further demonstrated the importance of interfacial modification for enhancement of triboelectric performance, illustrating that the interface issues should be taken into consideration in doping triboelectric composites for high output performance TENG.