Ultrathin porous electrode coatings for improved battery performance (POROBAT) (POROBAT)

Lithium-based batteries will play an increasingly important role in electrical energy storage because of their high energy density. However, current Li-ion technology is insufficient to meet long-term needs (e.g., extended-range electric vehicles). Although intense research efforts have led to significant progress, a major limiting factor is the low cathode capacity. Sulfur is one of the most promising cathode materials because of its high theoretical capacity, five times that of Li-ion cathodes, and low cost. However, the commercialization of Li–S batteries is hindered by their poor cycle life. Rapid capacity fading is caused by soluble polysulfide intermediates that diffuse through the electrolyte and react at the anode, thereby causing sulfur loss and a lowered coulombic efficiency. None of the current strategies to confine these polysulfides to the cathode have proven entirely satisfactory. Here, two research teams at Fudan University (China) and KU Leuven (Belgium) combine their expertise to propose a new strategy to block polysulfide diffusion: depositing an ultra-thin,  pinhole-free molecular sieve layer directly on an optimized carbon cathode. The pore size in the molecular sieve is perfectly uniform and selected to block polysulfides but let Li+ ions pass through. Although the proposed work focuses on demonstrating and understanding the underlying scientific concepts, the proposed methodology can be scaled in an  economical way.