Triboelectric Nanogenerators Based on Agricultural Husk Waste: A Focused Review on Material Design and Energy Performance

Abstract

The increasing demand for sustainable energy solutions and environmentally responsible waste management has encouraged the exploration of agricultural residues as functional materials for energy harvesting technologies. Among these residues, agricultural husks represent an abundant and underutilized lignocellulosic resource with intrinsic structural and chemical characteristics that are advantageous for triboelectric nanogenerators (TENGs). This review provides a focused and systematic analysis of agricultural husk–derived materials for TENG applications, with particular emphasis on material design strategies and energy performance. The unique natural architecture of husks, including their fibrous morphology, inherent surface roughness, abundant hydroxyl functional groups, and, in some cases, silica-rich composition, plays a decisive role in charge generation and retention. Various processing approaches such as mechanical grinding, nanoporous silica conversion, chemical functionalization, and composite integration are critically discussed in relation to their influence on electrical output parameters, including open-circuit voltage, short-circuit current, and power density. Reported studies demonstrate that rational material engineering significantly enhances triboelectric performance and enables practical applications such as wearable sensors, smart agriculture monitoring, portable electronics, and low-power IoT systems. Despite promising progress, challenges remain in terms of biomass variability, moisture sensitivity, long-term durability, and large-scale fabrication. Future development should focus on standardized processing, environmentally compatible modification strategies, and fully biomass-derived device architectures to improve reliability and sustainability. Overall, this review establishes a comprehensive framework for transforming agricultural husk waste into high-performance triboelectric materials and highlights their potential as a viable platform for next-generation self-powered energy systems.