Tunable reaction potentials in open framework nanoparticle battery electrodes for grid-scale energy storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The electrical grid requires efficient energy storage solutions for stability and load management.
• Current battery technologies face limitations in power, cycle life, energy efficiency, and cost.
• Aqueous sodium and potassium ion electrolytes offer safe and inexpensive alternatives for electrochemical energy storage.

Purpose of the Study:

• To investigate the tunability of reaction potentials in copper-nickel alloy hexacyanoferrate nanoparticles.
• To assess the electrochemical performance and structural integrity of these novel materials.
• To enable the development of advanced battery cells utilizing the full stability window of aqueous electrolytes.

Main Methods:

• Synthesis of copper-nickel alloy hexacyanoferrate nanoparticles.
• Structural characterization using X-ray diffraction and TEM energy dispersive X-ray spectroscopy.
• Electrochemical performance evaluation via galvanostatic cycling in aqueous sodium and potassium ion electrolytes.

Main Results:

• Copper and nickel form a fully miscible solution within the hexacyanoferrate framework without structural disruption.
• Copper-nickel hexacyanoferrate demonstrates reversible sodium and potassium ion intercalation for over 2000 cycles.
• Capacity retentions of 100% for sodium and 91% for potassium ion intercalation were achieved.
• Reaction potential is tunable by adjusting the copper-to-nickel ratio.

Conclusions:

• Copper-nickel hexacyanoferrate nanoparticles offer tunable electrochemical properties and exceptional cycle stability.
• These materials are promising electrode candidates for high-performance aqueous sodium and potassium ion batteries.
• The ability to tune reaction potential facilitates the design of full cells optimized for aqueous electrolyte systems.