A Strategy for Anode Recovery and Upgrading by In Situ Growth of Iron-Based Oxides on Microwave-Puffed Graphite

Faced with the increasing volume of retired lithium-ion batteries (LIBs), recycling and reusing the spent graphite (SG) is of great significance for resource sustainability. Here, a facile method for transforming the SG into a carbon framework as well as loading Fe₂O₃ to form a composite anode with a sandwich structure is proposed. Taking advantage of the fact that the layer spacing of the spent graphite naturally expands, impurities and intercalants are eliminated through microwave thermal shock to produce microwave-puffed graphite (MPG) with a distinct three-dimensional structure. Based on the mechanism of microwave-induced gasification intercalation, a Fe₂O₃-MPG intercalation compound (Fe₂O₃-MPGIC) anode material was constructed by introducing iron precursors between the framework layers and subsequently converting them into Fe₂O₃ through annealing. The Fe₂O₃-MPGIC anode exhibits a high reversible capacity of 1000.6 mAh g^-1 at 200 mA g^-1 after 100 cycles and a good cycling stability of 504.4 mAh g^-1 at 2000 mA g^-1 after 500 cycles. This work can provide a reference for the feasible recycling of SG and development of high-performance anode materials for LIBs.