Low-pressure air plasma-treated polytetrafluoroethylene surface for efficient triboelectric nanogenerator

In this study, an Al-PTFE triboelectric nanogenerator (TENG) that converts mechanical energy into electricity was investigated. The finite element analysis simulation was performed to illustrate the influence of surface engineering of the Al-PTFE TENG on electrostatic properties, especially at the edges of the TENG. The triboelectric performance of the TENG was improved through surface modifications of the PTFE using low-pressure air plasma treatment. The output voltage increased from 13 V in the untreated sample to 90 V in the 6 min plasma-treated sample under an applied force of 3 N. The maximum power density of the 6 min plasma-treated sample was calculated to be 24 times higher than that of the untreated sample. The enhanced triboelectric performance was attributed to the formation of nanostructured surface which had higher surface area of PTFE and better effective contact area between the Al and PTFE. The air plasma treatment modified the chemistry of the PTFE surface by creating new functional groups and carbon dangling bonds, which act as electron acceptor sites. Therefore, the electron transfer from Al to PTFE was facilitated, and better triboelectric performance was achieved. The 6 min plasma-treated TENG successfully powered electronic devices such as stopwatches and calculators.