High Energy Density\nLithium–Sulfur Batteries\nBased on Carbonaceous Two-Dimensional Additive Cathodes

Abstract

The increasing demand for electrical energy storage makes\nit essential\nto explore alternative battery chemistries that overcome the energy-density\nlimitations of the current state-of-the-art lithium-ion batteries.\nIn this scenario, lithium–sulfur batteries (LSBs) stand out\ndue to the low cost, high theoretical capacity, and sustainability\nof sulfur. However, this battery technology presents several intrinsic\nlimitations that need to be addressed in order to definitively achieve\nits commercialization. Herein, we report the fruitfulness of three\ndifferent formulations using well-selected functional carbonaceous\nadditives for sulfur cathode development, an in-house synthesized\ngraphene-based porous carbon (ResFArGO), and a mixture of commercially\navailable conductive carbons (CAs), as a facile and scalable strategy\nfor the development of high-performing LSBs. The additives clearly\nimprove the electrochemical properties of the sulfur electrodes due\nto an electronic conductivity enhancement, leading to an outstanding\nC-rate response with a remarkable capacity of 2 mA h cm^–2 at 1C and superb capacities of 4.3, 4.0, and 3.6 mA h cm^–2 at C/10 for ResFArGO₁₀, ResFArGO₅, and CAs,\nrespectively. Moreover, in the case of ResFArGO, the presence of oxygen\nfunctional groups enables the development of compact high sulfur loading\ncathodes (>4 mg_S cm^–2) with a great\nability\nto trap the soluble lithium polysulfides. Notably, the scalability\nof our system was further demonstrated by the assembly of prototype\npouch cells delivering excellent capacities of 90 mA h (ResFArGO₁₀ cell) and 70 mA h (ResFArGO₅ and CAs cell) at\nC/10.