Preparation of porous carbon with high performance as lithium-ion battery anode utilizing FeCl3/ZnCl2 as modifying agents

The anode materials for lithium-ion batteries (LIBs) are prepared by one-step carbonization using urea-impregnated cotton stalk (CS) as a carbon precursor and ZnCl2 and FeCl3 as an activator and catalyst, respectively. The addition of ZnCl2 contributes to the development of mesopore. Incorporating FeCl3 improves the graphitization of porous carbon, but has no significant effect on layer spacing. In addition, FeCl3 catalysis can increase the specific surface area and pore volume of porous carbon, especially the development of pore structure below 10 nm. In terms of electrochemical performance, the porous carbon is prepared at CS: ZnCl2: FeCl3 = 1:1:1 possessed the best performance, with a reversible capacity of 487.7 mAhg−1 after 100 charge–discharge cycles at 0.1 Ag−1 and specific capacity retention of 83.61 %. This study greatly improves the cycling stability of the battery while reducing the amount of mixed salt, which is extremely significant for subsequent research.