Separation and recovery of carbon powder in anodes from spent lithium-ion batteries to synthesize graphene

Abstract

Based on the structural characteristics of the anodes of lithium-ion batteries, an improved Hummers’ method is proposed to recycle the anode materials of spent lithium-ion batteries into graphene. In order to effectively separate the active material from the copper foil, water was selected as an ultrasonic solvent in this experiment. In order to further verify whether lithium ions exist in the active material, carbon powder, it was digested by microwave digestion. ICP-AES was then used to analyse the solution. It was found that lithium ions were almost non-existent in the carbon powder. In order to further increase the added value of the active material, graphene oxide was obtained by an improved Hummers’ method using the carbon powder. The graphene material was also reduced by adding vitamin C as a reducing agent through a chemical reduction method using graphene oxide. Meanwhile, the negative graphite, graphite oxide and graphene samples were characterized by XRD, SEM, FTIR and TEM. The conductivity of the negative graphite, graphite oxide and graphene was tested. The results show that graphene prepared by a redox method has a better layered structure, less impurities and oxygen groups in its molecular structure, wider interlayer spacing and smaller resistivity.

Synthesizing High‐quality Graphene from Spent Anode Graphite and Further Functionalization Applying in ORR Electrocatalyst

“…In this experiment, the thickness of 45 graphene flakes were measured and the number of layers is calculated, ranging from 2 to 9. Simultaneously, the yield of graphene is about 84.3 %, which is higher than that of most reports [22,26–27,48] …”

“…Simultaneously, the yield of graphene is about 84.3 %, which is higher than that of most reports. [22,[26][27]48] In order to better understand the reduction effect of G/T-rGO, the reduced graphene oxides were also prepared through hydrazine hydrate (HH-rGO), glucose (G-rGO) and thermal treatment (T-rGO), respectively. In comparison to thermal reduction, the chemical reduction has a weaker ability to remove the oxygen containing groups because of its limited capability to eradicate stable carbonyl and carboxyl groups, [49] which is confirmed by interlayer distance of chemically reduced graphene is larger than that of thermally reduced (Figure 5a).…”

“…The environmentally friendly route coupling the glucose reduction with thermal treatment to reduce the graphene oxide promotes the reduced graphene oxide with higher deoxygenation efficiency and quality. Compared with previous reports, [22–27] this method allowed the no toxic materials used, efficiency of oxidation and reduction improved, yield increased, and more importantly, the few‐layer graphene with high quality prepared. Furthermore, a simple chemical doping approach to prepare nitrogen‐doped graphene with incomparable capability in the application of oxygen reduction reaction catalyst was provided.…”

“…Additionally, Yang, et al. proposed a green redox method to manufacture the multiple‐layer graphene [27] …”

“…[25,26] Additionally, Yang, et al proposed a green redox method to manufacture the multiple-layer graphene. [27] On the other hand, although Pt/C catalyst is the application common choice in fuel cells, [28,29] it is expensive and unstable during long time operation. Massive research have been conducted to exploit new materials to replace the Pt catalysts and carbons with nitrogen doping are prevailing as substitutes because of the prominent electron transfer abilities.…”