MXene-Biochar Hybrid Inks for Triboelectric Energy Harvesting, Capacitor Charging, and Gait Monitoring

Muhammad Ajaz Ahmed1*, Joon Weon Choi1,2

(1Graduate School of International Agricultural Technology, Seoul National University,

2Institutes of Green-Bio Science and Technology, Seoul National University)

Abstract:  Developing sustainable electrodes for triboelectric nanogenerators requires balancing charge generation, mechanical stability, and electrical conductivity. In this study, biochar derived from oak mushroom logwood was combined with carbon black and Ti₃C₂ MXene to formulate water-based conductive hybrid inks for triboelectric energy harvesting. Well-delaminated MXene flakes, synthesized by HF etching of Ti₃AlC₂, were uniformly dispersed within the biochar matrix, enhancing conductive pathways and interfacial polarization. The biochar–carbon black–MXene hybrid electrode exhibited the best performance in a vertical contact–separation TENG, producing open-circuit voltages of ~180–200 V and short-circuit currents of 6–7 μA, significantly outperforming control electrodes. The device exhibited stable output over the frequency range of 0.8–2 Hz, demonstrated good durability, and displayed reliable load-dependent behavior. Harvested energy was successfully used for capacitor charging and demonstrated potential for gait monitoring. Overall, this work presents a scalable and sustainable strategy for high-performance triboelectric electrodes suitable for self-powered energy harvesting and wearable sensing applications.

Keywords: Biochar, MXene, TENG, Pressure sensing, Capacitor charging, Energy Harvesting