EPSRC-SFI: Next Generation Energy Autonomous Textile Fabrics based on Triboelectric Nanogenerators (NextGenT-TENG)

In recent years there has been a major surge in the use of wearable electronic devices & sensors (such as fitness monitors, smart watches, electrocardiogram (ECG) sensors etc.). The last decade has led to major advances in the capability of wearable systems; however, performance enhancement inevitably leads to miniaturisation of electronics meaning more sensors and increased power requirements going forward. At present, there is an urgent need to provide a sufficient and autonomous source of clean power to avoid dependence on cumbersome & environmentally unfriendly battery packs. The textile triboelectric nano generator (T-TENG) offers a solution. Triboelectric nano generators (TENGs) use the cyclic contact of two suitably chosen surfaces to convert mechanical energy to electrical energy. T-TENGs are simply TENGs where the tribo-contact materials are incorporated into wearable textiles capable of converting energy in human motions such as daily walking & arm movements into electricity. At present; however, T-TENG performance lags significantly behind that of conventional bulk TENGs and is insufficient to power most e-textile systems. This project will develop a next generation of high performance textile triboelectric nano generator capable of meeting the current and future energy requirements of wearable systems. It will also develop technology to incorporate the T-TENG in fully integrated energy autonomous fabrics. We will achieve this step-change in T-TENG performance via the following approach. First, the problem is intensely multidisciplinary and this has previously hampered development of a full picture. Therefore, this project unties the fields of electronic engineering, tribology, materials chemistry, and textiles technology to create the capability required to understand all key aspects of device performance. Next, recognising the need for a rigorous scientific foundation for device design, we will develop a fundamental understanding of the underlying physics of the tribo-contact of textiles. This will culminate in a predictive model for device performance accounting for both the mechanics and electrostatics of the T-TENG. We know that output is hugely linked to the amount of tribo-change density that can be developed at the interface. Here, we contend that maximising difference in election affinity (i.e. between the tribo-materials) and contact area will be critical. Therefore, we will optimise the materials, fibre architecture and surface topography of the textiles to maximise these two key parameters. On interface materials, we will implement the use of material pairs with maximum difference in electron affinity. This will take the form of metal oxide coated fibres in contact with conventional textile fibres such as polyester and polypropylene. On fibre architecture, we will use our predictive T-TENG model to design a fibre architecture that maximises contact area. On surface topography, we will pioneer the use of branching nano filaments or nano pillars to further enhance contact area. To implement these coatings and surface features on textile fabrics, the project will develop a number of novel processing techniques. All of these aspects will then be united in a single device design which will be further modified and refined. The optimised T-TENG will then be fully integrated with a textile based sensor system to form a fully energy autonomous fabric. Finally, a technology demonstrator will be built to demonstrate output performance to both academia & industry. We will work closely with our industrial partners Kyrima & Pireta who are both highly experienced in developing new technologies for the e-textiles industry. A successful outcome would mean that a host of wearable systems in the medical and entertainment sectors could be powered using a clean and free source of energy: that of simple everyday human motion.