The premise and promise of electrolyte manipulation and separator technology in potassium-ion batteries

In recent years, potassium-ion batteries (KIBs) have attracted significant attention as promising next-generation energy storage options, mainly because of potassium's natural abundance, cost-effectiveness, and favorable redox potential. While early research primarily concentrated on improving high-performance electrode materials, it is now increasingly clear that electrolyte engineering is equally critical, yet often overlooked, for affecting the electrochemical stability, ionic conductivity, safety, and overall performance of KIBs. This review encompasses the latest advancements in electrolyte formulations and design strategies, highlighting their crucial role in enhancing the capabilities and reliability of KIB technology. We explore the foundational principles and concepts that guide the development of electrolytes, including the selection of specific additives. We also review advances in solid-state electrolyte technology aimed at creating next-generation KIBs. Besides electrolyte formulation, we examine the evolution of separator materials and binder systems, which, although often seen as secondary, are vital to the durability and safety of KIB architectures. Our analysis of recent case studies and performance data highlights key challenges in the field and suggests strategic directions for future research. By reviewing these areas and outlining potential research paths, this article aims to provide a comprehensive framework to foster innovation in potassium-based energy storage systems.