Quantifying the Rate Performance of Potassium-Ion Batteries

Abstract

Lithium-ion batteries dominate battery research and industry due to their long research history and high energy density. However, increasing demand and limited lithium resources have raised lithium prices and battery costs, motivating interest in alternative chemistries. Potassium-ion batteries have recently attracted attention because potassium is more abundant and potentially lower cost, although the technology remains at an early stage and requires further insight for development. In this work, recently developed methods for rigorous analysis of electrode rate performance are applied to published rate-performance data from a wide range of potassium-ion batteries. Using specific capacity (mAh per g) versus charge and discharge rate curves, performance parameters are extracted to evaluate the applicability of the key model underlying these methods and to analyze opportunities for potassium-ion batteries. Relationships between these parameters and electrode properties are used to interpret performance trends and compare potassium-ion batteries with established technologies. The analysis shows that the model effectively fits potassium-ion battery rate-performance data and allows reliable extraction of performance parameters. While potassium-ion batteries generally exhibit lower specific capacities than lithium-ion and sodium-ion batteries, their upper limit of rate performance is found to exceed that of lithium-ion, sodium-ion, and related two-dimensional material electrodes, despite the larger atomic size and mass of potassium.