Tailoring 3D Carbon Foam using CNTs and MnO₂to Fabricate Stable Lithium/Dissolved Lithium Polysulfide Batteries

The lithium-sulfur (Li-S) battery is an ideal electrochemical energy storage system owing to the high theoretical energy density and acceptable cost of finance and the environment. However, some disadvantages, including low electrical conductivity, poor sulfur utilization, and rapid capacity fading, obstruct its practical application. In this work, 3D carbon foam from a melamine resin is synthesized via high-temperature calcination. Carbon nanotubes (CNTs) and MnO2 are utilized to tailor the properties of the 3D cathode collector in the liquid Li2S6-containing Li-S battery without additional conductive agents, binders, and aluminum foil. Herein, the decorated MnO2 on the carbon fiber foam prolongs the lifespan of the Li-S battery, and adding CNTs is beneficial to enhance the capacity and cyclic performance of the Li-S battery under high sulfur loading. The Li-S battery with a sulfur loading of 3 mg cm-2 possesses a reversible capacity of 437.9 mA h g-1 after 400 cycles at 0.1 C. The capacity could be maintained at 568 mA h g-1 at 0.1 C after 80 cycles when the sulfur loading increases to 6 mg cm-2.