High-energy density cellulose nanofibre supercapacitors enabled by pseudo-solid water molecules

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Conventional supercapacitors and lithium-ion batteries face limitations in energy density and charging speed.
• Amorphous cellulose nanofibers (ACNF) present a promising scaffold for novel energy storage materials.

Purpose of the Study:

• To develop and characterize a novel amorphous cellulose nanofibre (ACF) supercapacitor with enhanced energy density and high-power performance.
• To investigate the mechanism of energy storage in ACF supercapacitors utilizing pseudo-solid water molecules.

Main Methods:

• Integration of a single layer of pseudo-solid water molecules with cellulose nanofibers (CNFs) to form an electric double layer.
• Electrochemical characterization to determine energy density, power density, and voltage performance.
• Analysis of the charge storage mechanism involving proton polarization during water electrolysis.

Main Results:

• The ACF supercapacitor exhibits superior electric storage capacity and high-power density compared to conventional devices.
• A substantial energy density of 8.55 J/m² was achieved.
• Enhanced energy storage is attributed to the polarization of protons and electrons on oxygen atoms during water electrolysis starting at 1.23 V.

Conclusions:

• The developed ACF supercapacitor demonstrates significant promise for high-performance energy storage.
• Improvements in energy density can be achieved through optimizing CNF density and charging current.
• This technology is well-suited for integration into flexible and renewable paper-based electronic devices.