Regeneration of spent LiFePO4 cathode materials using solid state method and electrochemical performance
(2.Key Laboratory of Renewable Energy, Chinese Academy of Sciences, Guangzhou, Guangdong, China 510640)
(3.Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou, Guangdong, China 510640)
【Abstract】The recycled cathode material was obtained after removing the binder of the scrap electrode by heat treatment. The regenerated materials were obtained by high temperature solid state method that adding different proportions of Li, Fe, and P element sources to the recycled material based on quantitative analysis. In this paper, the influence of impurities on regenerated materials was investigated and the optimal proportion of regenerative reaction materials was obtained. The results show that the Fe2P impurity occurs during the regeneration process. The diffraction characteristic peaks of the Fe2P phase gradually decline with the increase in Li, Fe and P element sources. The presence of Fe2P phase decreases the specific capacity of the sample due to the low content of LiFePO4 active material. The morphology of regenerated materials tends to become densification as the proportions of Li, Fe and P element sources increase. The fine and close microstructure decreases the capacity and cycle performance of regenerated materials. The initial specific discharge capacities of the recycled material, stoichiometric regenerated material and excess element sources regenerated material are 103.4, 115.8 and 134.0 mA·h·g−1, respectively. Compared with that of the recycled material, the initial specific discharge capacities of the two regenerated materials are improved by 11.99% and 29.59%, respectively. The discharge capacities of the above three materials after 50 cycles are 100.9, 108.0 and 115.3 mA·h·g−1, respectively.
【Keywords】 scrap Li-ion battery; lithium iron phosphate; element supplement; recovery; regeneration; electrochemistry;
(Translated by REN XF)
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