Liquid Metal Particles–Graphene Core–Shell Structure Enabled Hydrogel-Based Triboelectric Nanogenerators

TL;DR

A new triboelectric material is created using liquid metal particles and graphene in a hydrogel, offering high performance for flexible, self-powered electronics.

Contribution

A redox reaction method is introduced to create LMP@rGO core–shell structures in hydrogels, enhancing triboelectric performance.

Findings

LMP@rGO/PAA hydrogels generate enough power to illuminate over half of 504 series-connected LEDs.

The composite shows improved dielectric constant and charge retention while maintaining soft mechanical compliance.

Increasing GO content enhances core–shell formation, leading to higher electrical performance.

Abstract

The development of flexible and self-powered electronic systems requires triboelectric materials that combine high charge retention, mechanical compliance, and stable dielectric properties. Here, we report a redox reaction approach to prepare liquid metal particle-reduced graphene oxide (LMP@rGO) core–shell structures and introduce into a poly(acrylic acid) (PAA) hydrogel to create a high-performance triboelectric layer. The spontaneous interfacial reaction between gallium oxide of LMP and graphene oxide produces a conformal rGO shell while simultaneously removing the native insulating oxide layer onto the LMP surface, resulting in enhanced colloidal stability and a controllable semiconductive bandgap of 2.7 (0.01 wt%), 2.9 (0.005 wt%) and 3.2 eV (0.001 wt%). Increasing the GO content promotes more complete core–shell formation, leading to higher zeta potentials, stronger interfacial polarization, and higher electrical performance. After embedding in PAA, the LMP@rGO structures form hydrogen-bonding networks with the hydrogel nature, improving both dielectric constant and charge retention while notably preserving soft mechanical compliance. The resulting LMP@rGO/PAA hydrogels show enhanced triboelectric output, with the 2.0 wt/vol% composite generating sufficient power to illuminate more than half of 504 series-connected LEDs. All the results demonstrate the potential of LMP@rGO hydrogel composites as promising triboelectric layer materials for next-generation wearable and self-powered electronic systems.

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