# 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.

## Key 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.