Understanding the chemistry of re-emerging proton batteries

Proton battery (PB) technology has regained attention in recent years as a promising energy storage alternative to conventional lithium-ion batteries due to its excellent electrochemical performance, scalability, and environmental friendliness. To assess its potential, we provide a comprehensive review of its re-emergence, including its historical background, construction, working principles, and favorable materials. The growing global demand for energy storage and the role of PBs in addressing this need are highlighted, and the historical background tracing the evolution of PBs, from their early conceptualizations to recent advancements, is covered. Battery components such as electrodes and electrolytes are discussed, and the mechanisms underlying proton conduction, catalytic activity, and surface chemistry at the electrode-electrolyte interfaces are also summarized. Furthermore, various proton-conducting materials and media are examined, along with a discussion on their structural and electrochemical properties. Finally, a SWOT analysis covers the strengths, weaknesses, opportunities, and threats of PBs and offers valuable perspectives regarding R&D prospects. This review emphasizes the need for continued innovation to unlock the full potential of PBs as sustainable energy storage alternatives.