FeIII Chelated with Humic Acid with Easy Synthesis Conditions and Good Performance as Anode Materials for Lithium-Ion Batteries

In this work, we prepared a green, cheap material by chelating humic acid with ferricions (HA-Fe) and used it as an anode material in LIBs for the first time. From the SEM, TEM, XPS,XRD, and nitrogen adsorption-desorption experimental results, it was found that the ferric ion canchelate with humic acid successfully under mild conditions and can increase the surface area of materials. Taking advantage of the chelation between the ferric ions and HA, the capacity of HA-Feis 586 mAhg(-1)at 0.1 Ag(-1)after 1000 cycles. Moreover, benefitting from the chelation effect, the activation degree of HA-Fe (about 8 times) is seriously improved compared with pure HA material(about 2 times) during the change-discharge process. The capacity retention ratio of HA-Fe is 55.63%when the current density increased from 0.05 Ag(-1)to 1 Ag(-1), which is higher than that of HA(32.55%) and Fe (24.85%). In the end, the storage mechanism of HA-Fe was investigated with ex-situXPS measurements, and it was found that the C=O and C=C bonds are the activation sites for storageLi ions but have different redox voltages.

Automated summary

In this study, a green and cheap material was prepared by chelating humic acid with ferricions and used as an anode material in lithium-ion batteries for the first time. The results showed successful chelation between ferric ions and humic acid, leading to increased surface area of the material. The material demonstrated improved capacity retention and activation degree compared to pure humic acid material.