Design and synthesis of nitrogen and sulfur co-doped porous carbon via two-dimensional interlayer confinement for a high-performance anode material for lithium-ion batteries

Abstract

Nitrogen (N) and sulfur (S) co-doped porous carbon materials (NSPCs) have been prepared by the two-dimensional interlayer confinement effect of a layered double hydroxide (LDH). The NSPCs fabricated by this method have a large specific surface area of 1493.2 m² g⁻¹ and contain plenty of micropores and mesopores, which arise from either the carbonization of organic polymers and the catalytic effect of iron in LDH layers in the calcination process, or the elimination of metal oxides produced by the LDH hosts in acid dissolution. The prepared material exhibits an excellent reversible specific capacity of 1175 mA h g⁻¹ at 0.5C after 120 cycles. High specific discharge capacities are maintained at fast C rates, e.g. 765, 600, 510, 419, 398, 360, and 326 mA h g⁻¹ at 1, 2, 6, 15, 20, 30 and 60C, with 15 cycles at each step. We found that the improved electrochemical performance is due to the large quantity of edge defects, and the micropores and mesopores in the material which can provide extra Li storage regions.