From Metals to Polymers: Material Evolution and Functional Advancements in Current Collectors

The rapid advancement of rechargeable batteries is hindered by insufficient energy density, limited design flexibility, and safety concerns, which pose significant challenges to their practical application. This review summarizes the crucial yet often overlooked role of current collectors in addressing these challenges. Recent progress across four types of current collectors, deriving from metal foils, carbonaceous substrates, conductive polymers, and organic–inorganic hybrids is systematically analyzed. Metal foils, as the most widely used current collectors, now face challenges including corrosion susceptibility and high volumetric density. Carbonaceous and polymer-based alternatives offer lightweight design and structural flexibility, but face limitations in conductivity and scalable production. Notably, organic–inorganic hybrid current collectors, leveraging material engineering and hierarchical design, offer a promising avenue to enhance battery safety and intelligence. Further, potential directions for current collector development, emphasizing 1) enhanced battery performance, 2) multiscale structural adaptability, and 3) integrated multifunctional design, providing prospective insights for next-generation energy storage devices are outlined.