Potassium-Ion Battery Anodes: Mechanistic Frameworks, Electrolyte/Binder Integration, and Roadmap Toward Commercialization

Potassium-ion batteries (KIBs) are gaining attention as a sustainable alternative to lithium- and sodium-based systems, benefiting from the abundance of potassium, low-cost salts, and the potential use of biomass-derived carbons. Their favorable redox potential, compatibility with aluminum current collectors, and stable SEI formation provide unique advantages, though the large ionic radius of K⁺ poses challenges for designing stable and high-capacity anodes. This review categorizes KIB anodes into five classes—alloy-based, intercalation-type, conversion-type, conversion–intercalation hybrids, and organic systems—and critically evaluates their redox mechanisms, electrochemical performance, and structural evolution. Beyond the active materials, we highlight the often-overlooked but crucial influence of electrolyte formulations (e.g., potassium hexafluorophosphate (KPF₆), potassium bis(fluorosulfonyl)imide (KFSI), or concentrated electrolytes) and binder chemistries in governing solid electrolyte interface (SEI) stability, ion transport, and electrode durability. We also discuss recent commercialization efforts, including Natron Energy's Prussian blue–based systems, and outline a forward-looking roadmap that integrates materials innovation with electrode–electrolyte engineering and sustainability principles. By bridging mechanistic understanding with industrial perspectives, this review provides guidance for advancing KIBs toward practical, environmentally responsible energy storage solutions.