Triboelectric Nanogenerators Based on Immobilized Living Microalgae for Biomechanical Energy Harvesting

Abstract

Triboelectric nanogenerators (TENGs) are gaining attention for energy supply because of higher demands in decentralized energy production. TENGs are known for being self-energy harvesters, converting wasted mechanical energy to useful electrical energy under an ambient environment. Advantages of TENGs include a clean energy supply, a wide range of materials selection, and an energy scavenging capability in the ambient environment. However, TENGs still suffer from their low electrical outputs compared to existing electrical supplies such as fuel cells and batteries. In bio-photovoltaic (BPV), there has been an interest in the use of microalgae, which are photosynthetic microorganisms capable of carbon capture and generating bioelectricity both day and night through electron transport chains via photosynthesis and cell respiration. To increase the current output of BPV, many have tried to immobilize living microalgal cells onto electrodes for higher mass transfers leading to higher photosynthetic rates. In this study, we have used immobilized living microalgae (Chlorella sp.) onto aluminium sheets to fabricate the TENG systems and investigate biomechanical energy harvesting. This proof of concept shows that this integration of microalgae with TENG can enhance the voltage and current output achieved by the dual operation modes of TENG. One issue raised during the tests was maintaining microalgae alive for several days, which has given opportunities for further studies in nutrient and light supplies to this innovative sustainable hybrid technology. The results confirm that the microalgae can be an excellent triboelectric layer in TENG for biomechanical energy harvesting. Graphical Abstract: [Figure not available: see fulltext.]. © 2023, The Author(s) under exclusive licence to The Korean Institute of Metals and Materials.