Enhanced Interfacial Properties of Thickness-Tunable Carbon Nanosheets for Advanced Lithium–Sulfur Batteries

We reported a template-free and facile synthetic route to engineer thickness-tunable ultrathin two-dimensional (2D) porous carbon nanosheets (U-PCNS) for advanced lithium–sulfur batteries. The thickness-dependent interfacial properties, e.g., the specific surface area, porosity, and the oxygen doping level, have significantly improved mass/charge transfer and polysulfide chemisorption of U-PCNS. It is worth noting that the thickness of U-PCNS is vitally sensitive to the initial water concentration, which manipulates viscosity of hydrogels, hydrogen bonding between polymers, polymer assembly manner, and thus the thickness of as-prepared carbon nanosheets. The enhanced interfacial properties of U-PCNS endow lithium–sulfur cathodes with excellent rate capability at 0.2C, outstanding cycle life over 1000 cycles, and an area-specific capacity up to 4.02 mAh cm–2.