Cellulose-based triboelectric nanogenerators for wearable electronics: From materials design to multifunctional integration.

The rapid development of wearable electronics requires sustainable, flexible, and comfortable power sources for harvesting low-frequency biomechanical energy. Triboelectric nanogenerators (TENGs) offer a promising route for self-powered wearable systems, but many conventional synthetic polymer tribolayers suffer from limited breathability, poor degradability, and insufficient long-term wearing comfort. Cellulose-based materials, with renewability, biodegradability, biocompatibility, lightweight structure, mechanical flexibility, and abundant functional groups, provide attractive alternatives for wearable TENGs. Different from a general summary of cellulose-based TENGs, this review provides a wearable-oriented perspective by linking the intrinsic properties of cellulose with fabrication strategies, structure-dependent device configurations, and practical wearable applications. Specifically, the design principles of TENGs and the material basis of cellulose are first introduced, followed by a discussion of representative fabrication strategies, including direct mixing, vacuum filtration, freeze-drying, chemical crosslinking, and spinning. Paper-, textile-, film-, aerogel-, and hydrogel-based TENGs are then comparatively reviewed in terms of their structural features, output regulation, operational stability, wearing comfort, and application scenarios. Remaining challenges, including limited electrical output, moisture-induced charge dissipation, mechanical durability, scalable fabrication, and system-level integration, are finally discussed to guide future development of cellulose-based wearable TENGs.