Towards outstanding energy-efficiency in a recyclable triboelectric nanogenerator based on a soft-rough composite material

Abstract

Energy efficiency vs. degradability of materials making up triboelectric nanogenerators (TENGs) is critical for recyclable energy sources. In this work, we first compared voltage output expectation (V_exp) of contact-separation TENG consisting of two tribo-layers: paper and common plastics used in packaging (both non-biodegradable and biodegradable). Detailed analysis based on atomic force microscopy and capacitance measurements demonstrated surface roughness of soft-rough biodegradable polymers (SRBPs) is expected to yield larger V_exp, predictably. A SRBP composite-based TENG was expected to show ∼7.2 times larger V_exp than a hard-flat nonbiodegradable plastic, demonstrating promising charge transfer efficiency; while the measured voltage (V_mea) was only 6.5% of V_exp. This was unlike the other plastics, including a non-composite SRBP, (V_mea/V_exp ∼0.36) and the low V_mea/V_exp in the SRBP composite-based TENG was attributed to intrinsic material properties. Also, energy conversion efficiency in TENG-based on SRBPs was more than double of hard-flat plastics. This shows the potential of the composite SRBP-based TENG as effective energy harvester.