Regulating Fast Anionic Redox for High-Voltage Aqueous Hydrogen-Ion-based Energy Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hydrogen ions (H+) are ideal charge carriers for energy storage due to their conductivity and small size.
• Constructing high-voltage two-electrode hydrogen-ion energy storage (HES) systems is challenging due to limitations in efficient cathodic energy storage.

Purpose of the Study:

• To develop a high-voltage HES system by addressing the limitations of cathodic energy storage.
• To explore the use of reduced graphene oxide (rGO) with redox additive electrolytes for fast anionic redox at the cathode.
• To couple rGO cathodes with Ti3C2Tx anodes for enhanced HES performance.

Main Methods:

• Utilized reduced graphene oxide (rGO) as a cathode material with redox additive electrolytes to achieve high potential fast anionic redox.
• Employed Ti3C2Tx as an anode material for storing hydrogen ions.
• Constructed an asymmetric HES device by coupling the rGO cathode and Ti3C2Tx anode.

Main Results:

• Achieved a high operating voltage of 1.8 V with a plateau voltage of 1.2 V in the HES device.
• The asymmetric rGO//Ti3C2Tx HES demonstrated a specific energy of 34.4 Wh/kg, a significant increase from 2.2 Wh/kg in symmetric Ti3C2Tx//Ti3C2Tx cells.
• Attained an energy density of 23.7 Wh/kg at a high power density of 22.5 kW/kg.

Conclusions:

• The study presents a viable strategy for creating high-voltage HES full cells.
• The integration of fast anionic redox cathodes with hydrogen-ion storing anodes offers a promising pathway for advanced energy storage solutions.
• This work provides a novel guideline for the development of efficient and high-performance HES systems.