Reflections on boosting wearable triboelectric nanogenerator performance via interface optimisation

An increasing need to harness power from our surroundings has led researchers to delve into the concept of green energy production from our environment. Textile and wearable triboelectric nanogenerators (t-TENGs or w-TENGs) are a promising option in this regard. Textile and wearable triboelectric nanogenerators can convert mechanical energy present in fabric movements into electrical power using modified textile materials or alternative base materials (such as polyester, PDMS, silicone, etc.). These devices are intended to be mounted on garments or directly on the skin making them highly portable, but could also be installed in any other areas where mechanical energy is present (shoes, floor, bag packs etc.). They have proven to be capable of generating sufficient energy to power some low power devices and sensors. A key present limitation for textile TENGs is their low output compared to non-textile film based TENGs. In this review, we reflect on the task of boosting textile TENG performance via interface modification. Specifically, the paper surveys the improvements that have been possible via surface modification of textiles using different metals or metal oxides and plasma processes. Finally, some key areas are highlighted from a tribology and contact mechanics perspective that may have the potential to lead to further significant enhancements in performance; namely, designing fabric interfaces to boost contact area.