Ice/salt assisted synthesis of ultrathin two-dimensional nitrogen doped carbon nanosheets for fast lithium storage

Abstract

Two-dimensional carbon nanosheets have garnered considerable interest as promising anode materials in energy storage devices due to their large specific surface area and excellent conductivity. The efficient synthesis of ultrathin nitrogen-doped carbon nanosheets is achieved with the aid of cysteine, employing a green ice/salt-assisted strategy. Ice influences the growth direction of salt crystals and determines the distribution of sodium lignosulfonate on the surfaces of both ice and salt crystals. The introduction of methionine incorporates heteroatoms, altering the electronic structure and chemical activity of the material, thereby effectively enhancing its lithium storage performance. The initial charge capacity of the optimized sample reached 766.4 mA h g−1 at a current density of 0.2 A g−1, maintaining a capacity of 571.1 mA h g−1 after 100 cycles. This study presents an innovative method for fabricating ultrathin carbon nanosheets using eco-friendly, cost-effective sodium lignosulfonate, showcasing a promising candidate for lithium-ion batteries and future energy storage technologies.