# Polyhydroxy Hydrogel Electrolyte with In Situ Tuned Interface Chemistry for Ultra-Stable Biosensing-Compatible Zinc Batteries

## TL;DR

A new hydrogel electrolyte improves zinc battery stability and enables real-time biosensing for wearable health monitoring.

## Contribution

A polyhydroxy hydrogel electrolyte with in situ interface tuning for ultra-stable zinc batteries and biosensing integration.

## Key findings

- Zn anodes achieved 3300 hours of dendrite-free plating/stripping with 99.6% coulombic efficiency.
- Flexible Zn//I2 batteries retained 94.9% capacity after 9000 cycles.
- An integrated biosensing platform enabled real-time physiological signal monitoring.

## Abstract

Polyhydroxy hydrogel electrolyte enables in situ dual regulations of Zn-electrolyte interfacial chemistry and bulk electrolyte properties.Reversible Zn anodes with exceptional cycling stability and perfect coulombic efficiency are achieved.A self-powered biosensing platform that integrates Zn//I2 batteries with hydrogel sensor achieves real-time physiological monitoring.

Polyhydroxy hydrogel electrolyte enables in situ dual regulations of Zn-electrolyte interfacial chemistry and bulk electrolyte properties.

Reversible Zn anodes with exceptional cycling stability and perfect coulombic efficiency are achieved.

A self-powered biosensing platform that integrates Zn//I2 batteries with hydrogel sensor achieves real-time physiological monitoring.

The online version contains supplementary material available at 10.1007/s40820-025-02061-z.

Aqueous zinc batteries (ZBs) represent a promising sustainable and safe energy storage technology, yet their widespread adoption is impeded by persistent interfacial instabilities at Zn anodes. This study reports a polyhydroxy hydrogel electrolyte (PASHE) with in situ regulated interface chemistry suitable for biosensing compatible ZBs. Benefiting from the well-integrated interface via in situ strategy, the hydroxyl-rich L-sorbose in PASHE establishes kinetically favorable Zn2+ transport pathways and regulates interfacial ion-adsorption hierarchies, synergistically homogenizing ion distribution and promoting preferential crystallographic orientation. Furthermore, PASHE constructs a low water-activity microenvironment via interfacial preferential adsorption, oxygen-rich solid electrolyte interphase evolution, and Zn2+ solvation sheath reconstruction. These effects enable Zn (002)-textured electrodeposition and inhibitory side reactions, achieving dendrite-free Zn plating/stripping with exceptional stability (3300 h in Zn//Zn cells) and near-perfect reversibility (average coulombic efficiency of 99.6% over 1200 cycles in Zn//Cu cells). This strategy delivers unprecedented cyclability in flexible Zn//I2 batteries (94.9% retention after 9000 cycles) and Zn-ion hybrid capacitors (98.0% after 43,000 cycles). Notably, we demonstrate an integrated biosensing platform that couples PASHE-based biosensor with cascaded Zn//I2 batteries, realizing real-time monitoring of physiological signals and biomechanical motions. This work proposes dual strategies of in situ approach and functional additive to design hydrogel electrolytes, bridging high-performance ZBs with next-generation biosensing technologies.

The online version contains supplementary material available at 10.1007/s40820-025-02061-z.