Aluminum Foil Crumpled Ball Based Triboelectric Nanogenerator for Ultralight, Low Noise, Highly Durable Self-Powered Portable Device

Recently, as modern society became more industrialized and the global population explodes, the world is facing a large amount of waste materials, which causes environmental problems such as soil pollution, air pollution, and water pollution Among the waste materials, aluminum foil, which is widely used for food, cosmetics, tobacco, and chemical products owing to its distinctive advantages of cheap, lightweight, good thermal conductivity, impermeability, and wide adaptability, occupies a significant proportion and the amount of waste foil is increasing with its usage. For example, estimates suggest that in Europe, almost 860,000 tons of aluminum foil has been produced per year. Also, in China alone, the amount of aluminum foil production is 3.65 Mt in 2017. Many of those aluminum foil is thrown as waste in a damaged state with contaminant materials and difficult to recycle, accordingly, most of waste foils are landfilled or incinerated, resulting in many harmful effects to nature environments. Accordingly, converting the waste aluminum foil into useful things may provide a new platform for addressing the environmental problems.<br/>In this regard, triboelectric nanogenerator (TENG), which converts ambient mechanical energy into electricity via contact electrification and electrostatic induction, is a promising option owing to its attractive characteristics, such as simple fabrication, wide material availability, and versatile operation modes. Although several research have hitherto been conducted to fabricate TENG utilizing aluminum foil, the conventional structures, especially plate to plate type, are disadvantageous to use recycled foil because used aluminum foils are generally wasted in state of torn and wrinkled, and commonly thrown away with contaminant materials. Furthermore, as electrical output performances of typical plate to plate type TENGs, which produce electricity by contact-separation process of different materials, are significantly affected by surface state of materials, these deformed and contaminated foils may have a negative influence on output performances. Therefore, for effectively utilizing these recycled aluminum foils into TENG, a novel structural design strategy, which can generate electricity through these deformed and contaminated foils, is highly desired.<br/>In this work, aluminum foil based crumpled ball TENG (AFCB-TENG) was proposed. Here, the aluminum foil which was commonly wasted as garbage is recycled, crumpled in a ball shape, generates electricity and powers electronics. Owing to the innovative crumpled foil design, AFCB-TENG exhibits the outstanding characteristics, such as ultralight, low noise, and highly durable, which is significantly advantageous and qualified as sustainable power sources. For generating high electrical output, AFCB-TENG was fabricated by air-breakdown model, which produces electricity via direct electron transfer in strong electric field. Therefore, AFCB-TENG achieved the high output performances, such as output peak voltage of 648 V, current density of 8.1 mA/cm³, and optimum power density of 162.7 mW/cm³. In addition, for maximizing the output performances, the structure of AFCB-TENG was quantitatively optimized according to various design parameters. The optimized AFCB-TENG demonstrated its high performances while driving 500 LEDs and powering 30 W commercial lamps. This work provides an innovative guideline for fabricating TENG with outstanding characteristics while not polluting our nature environment.