N, S Co-Doped Bagasse Mesoporous Carbon with Enhanced Electrochemical Performance

Abstract

Nitrogen-sulfur co-doped interconnected honeycomb sheet-like biomass carbon (N, S-BC) from low-cost agriculture waste-bagasse, was prepared by a simple and effective strategy of one step heat treatment with thiourea as doping agent. The mesoporous structure of N, S-BC shows an average pore diameter of 6–25 nm, a sheet thickness of 5–7 nm, and a relatively large BET surface area of 1576.7 m 2 g −1 . The N, S-BC anode material exhibits better electrochemical performance than the un-doped BC and the N, S single-doped BC (N-BC and S-BC). The N, S-co-doping makes the first discharge specific capacity of BC increase 105.9%, the first coulomb efficiency increase 22.8%, and the reversible capacity increase 187.2% after 50 cycles. After 200 cycles, A relatively high reversible capacity of 572.8 mAh g −1 even can be observed at a high current density of 2 A g −1 , which is 3.7 times that of BC and almost twice that of N-BC and S-BC. When using as LEDs lighting power supply, the brightness duration of N, S-BC cell shows longer than that of BC cell. The dynamic storage mechanism study results show that both the diffusion coefficient of lithium ions and capacitance contribution rate of N, S-BC are larger than those of BC. These enhanced electrochemical properties of N, S-BC are attributed to their high specific surface area, abundant uniform mesoporous structure of the honeycomb layer and defects, and the synergistic effect of diatomic doping. The one-step method of N, S co-doping technology for sheet-like porous biomass carbon could be used to synthesize high-performance lithium-ion battery electrode materials with cheap and readily available agricultural waste is used as precursors.