All-Cellulose Salt-Concentrated Hydrogel Electrolyte

Stable above 60 °C

Cotton cellulose and methylcellulose form a hydrophobic crosslinked network that maintains both mechanical integrity and ionic conductivity at high temperature, enabling zinc-ion hybrid supercapacitors to operate at 120 °C.

Ge, Xiang · Yao, Jianfeng

Angewandte Chemie - International Edition 2025

Specifications

Specific capacity at 120 °C

{'zh': '250.3', 'en': '250.3'} mAh g-1

Capacity retention after 10,000 cycles at 60 °C

{'zh': '85.4', 'en': '85.4'} %

Advantages

Thermally robust

Methylcellulose undergoes temperature-dependent hydrophobic interactions, stabilizing the homogeneous polymer-salt phase with cotton cellulose, thereby preserving both mechanical integrity and ionic conductivity above 60 °C.

Works at 120 °C

A zinc-ion hybrid supercapacitor using this gel delivers a specific capacity of 250.3 mAh g⁻¹ at 120 °C, confirming that the electrolyte remains functional at extreme heat.

10,000-cycle endurance

Retaining 85.4% capacity after 10,000 cycles at 60 °C indicates that the hydrogel maintains structural and electrochemical stability under prolonged thermal aging.

All-biobased composition

The gel network is built exclusively from cotton cellulose and methylcellulose, two natural polysaccharides, thereby avoiding synthetic polymers and reducing environmental impact.

Applications

• Zinc-ion hybrid supercapacitors：Heat-tolerant gel pushes zinc-ion hybrid supercapacitors beyond conventional temperature limits for high-temperature energy storage.
• High-temperature energy storage devices：The gel enables devices to deliver high specific capacity at 120 °C without auxiliary cooling.
• Heat-resistant hydrogels：Hydrophobic association suppresses water loss and preserves mechanical and conductive properties above 60 °C.