Characterisation and modelling of potassium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-ion batteries (KIBs) are a promising alternative to lithium-ion batteries (LIBs) due to reduced reliance on critical minerals.
• KIBs offer potential for superior fast-charging capabilities, supported by demonstrated fast K-ion electrolyte transport.
• Accurate characterization of electrode material properties is crucial for realizing KIB fast-charging potential, but has been lacking.

Purpose of the Study:

• To accurately characterize the solid-state diffusivity and exchange current density of key KIB electrode materials.
• To develop a comprehensive Doyle-Fuller-Newman model for a KIB full cell.
• To identify critical material properties limiting KIB rate capability.

Main Methods:

• Optimized material design and state-of-the-art analysis were employed.
• Accurate characterization of effective solid-state diffusivities and exchange current densities for graphite (negative electrode) and potassium manganese hexacyanoferrate (KMF) (positive electrode).
• Development of a Doyle-Fuller-Newman model simulating a KIB full cell with realistic geometry and loadings.

Main Results:

• Effective solid-state diffusivities and exchange current densities for graphite and KMF electrodes were accurately determined.
• A Doyle-Fuller-Newman model was successfully implemented for a KIB full cell.
• Key material properties limiting the rate capability of KIBs were identified.

Conclusions:

• This work provides crucial material property data for advancing KIB technology.
• The developed model aids in understanding and optimizing KIB fast-charging performance.
• Identifying rate-limiting properties is essential for the future development of high-performance KIBs.