Single atom metal and N co-doped porous carbons for high-performance lithium-ion batteries

Porous carbon materials are considered promising anodes for lithium-ion batteries (LIBs) due to their high theoretical capacities and rich natural resources. However, the poor cycle performance and sluggish lithium diffusion kinetics limit their application. Here, single atom metal (M = Fe, Co, Ni, and Mn) and N co-doped porous carbons (M-N-C) were successfully prepared by a polymer-pyrolysis method. single atom metal and N co-doping provided a larger number of anchoring sites for Li⁺ adsorption, enlarged the inter-distance of graphenes, and endowed overall atomic structural stability to the materials by constructing a coordination mode of M-N-C; the materials showed excellent cycle performance and rate performance, and after 1000 cycles, the discharge capacity was still 635 mA h g^-1 at 0.5 A g^-1. The galvanostatic charge/discharge curves and cyclic voltammetry of M-N-C revealed that bulk capacity arises from a capacitive-controlled process involving Li-ion adsorption/desorption on active site surfaces. In addition, Mn-N-C had excellent electrode kinetics, which showed smaller charge transfer resistance (21.4 Ω). This work provides inspiration for the design of superior porous carbons with a stable structure for lithium-ion batteries and energy storage.