Template-free preparation of porous Co microfibers from spent lithium-ion batteries as a promising microwave absorber

摘要

In order to take full advantage of the secondary resources,in this paper,we reported a template-free process to prepare porous Co microfibers from spent lithiumion batteries(LIBs).First,the waste LiCoO_(2) powders were leached by oxalic acid at a suitable temperature,and rodlike cobalt oxalate powders were obtained.Second,the porous Co microfibers were prepared by using the cobalt oxalate as precursors through a thermal decomposition at420 ℃ under nitrogen atmosphere.The prepared Co microfibers possess diameters of 1-2 μm,and each microfiber consists of small particles with size of100-200 nm.The Co microfibers(25 wt%)/paraffin composite exhibited excellent microwave absorption performance.When the sample thickness is 4.5 mm,the reflection losses reach-36.14 and-38.20 dB at 4.16 and 17.60 GHz,respectively,and the effective bandwidth reaches up to 5.52 GHz.This indicates that the Co microfibers can be used as a promising microwave absorber.Therefore,this paper demonstrates a novel process to make a high value-added product through recycling from the spent lithium-ion batteries.In addition,it is advantageous to eliminate the hazard of spent lithium-ion batteries and electromagnetic radiation to environment and human health.