Methyl Asymmetric Interference-Enhanced Dipole-Dipole Interaction for High-Performance Potassium-Graphite Battery...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-ion batteries offer an alternative to lithium-ion batteries, uniquely capable of using graphite anodes.
• Development has been hindered by the absence of high-voltage electrolytes compatible with graphite.
• This limitation restricts the performance and applicability of potassium-graphite battery systems.

Purpose of the Study:

• To design and develop a novel high-voltage electrolyte compatible with graphite anodes for potassium-ion batteries.
• To overcome the limitations of existing electrolytes and enable stable potassium-graphite battery operation.
• To enhance the energy density and cycling performance of potassium-graphite batteries.

Main Methods:

• Formulation of a high-voltage electrolyte utilizing methyl asymmetric interference-enhanced dipole-dipole interactions.
• Characterization of the electrolyte's electrochemical window and stability.
• Testing of potassium-graphite battery performance with Prussian blue analogue cathodes and graphite anodes.

Main Results:

• The developed electrolyte achieves an initial Coulombic efficiency of 86.5% by reducing K+ desolvation energy and forming a sulfur-rich solid electrolyte interface.
• A stable electrochemical window of 4.6 V was achieved at a low current density of 1 µA cm⁻².
• Potassium-graphite batteries demonstrated high energy densities (265.6 Wh kg⁻¹ to 306.2 Wh kg⁻¹) and excellent capacity retention (81.3% after 600 cycles).

Conclusions:

• The novel high-voltage electrolyte successfully enables stable and high-performance operation of potassium-graphite batteries.
• The electrolyte's compatibility with graphite anodes and high voltage stability opens new avenues for advanced energy storage.
• Demonstrated application potential in a functional pouch cell highlights the practical viability of this technology.