Tailoring carbon chains for repairing graphite from spent lithium-ion battery toward closed-circuit recycling

Graphite, as a strategic mineral resource, the recycling from spent lithium-ion batteries(LIBs) has attracted considerable attention for meeting considerable economic value. However, closed-circuit recycling still suffers from the lack of effective repair methods. Considering the existing defects, a series of Cchain length carbons have been successfully introduced to repair spent graphite. Obviously, with the evolution of carbon resources, the thickness and pores of the coating layer were tailored with the functional groups. Benefitting from the increased active sites and created fold structure, their coulombic efficiency is obviously restored from 14% to 86.89%, while the stable capacity is kept at approximately 384.9 mAh gafter 100 cycles. Moreover, their excellent rate properties are kept about approximately 200 mAh gat2 C, meeting the standard of commercial materials. Supported by the detailed kinetic behaviors, the enhanced rate is mainly dominated by pseudocapacitive behaviors, accompanied by deepening redox reactions. Meanwhile, the cost of the proposed approach for recycling spent graphite is 894.87 $ t^(-1),and the recycling profit for regenerating graphite is approximately 7000 $ t^(-1). Given this, this work is anticipated to shed light on the closed-circuit recycling of spent graphite and offer significant strategies to repair graphite.

Technology for recycling and regenerating graphite from spent lithium-ion batteries

With the annual increase in the amount of lithium-ion batteries(LIBs),the development of spent LIBs recycling technology has gradually attracted attention.Graphite is one of the most critical materials for LIBs,which is listed as a key energy source by many developed countries.However,it was neglected in spent LIBs recycling,leading to pollution of the environment and waste of resources.In this paper,the latest research progress for recycling of graphite from spent LIBs was summarized.Especially,the processes of pretreatment,graphite enrichment and purification,and materials regeneration for graphite recovery are introduced in details.Finally,the problems and opportunities of graphite recycling are raised.

废旧锂电池回收过程中氟的迁移及其原位掺杂再生制备LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)正极材料

氟是废旧锂电池回收难以回避的典型杂质元素,其迁移转化行为复杂,制约了高品质正极材料的可控再生制备.本研究通过揭示废旧锂电池在热解、浸出及高镍LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)材料再生过程中氟的迁移转化规律,为氟的定向调控及材料的可控再生制备奠定理论基础实验结果表明:热解过程中部分氟(45.71%)以气态热解产物的形式释放到大气中,而另一部分氟(52.34%)则向废三元材料的晶格内发生迁移,并随着湿法浸出溶解到镍钴锰的浸出液中.浸出液中少量的氟会在共沉淀制备前驱体过程中迁移到Ni_(0.9)Co_(0.05)Mn_(0.05)(OH)2前驱体材料,并随着配锂烧结掺杂到再生LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)材料表面.进一步通过调控氟含量发现,当浸出液中氟浓度控制在0.30 g L^(-1)时,引入到再生LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)材料中的氟不仅不会引起不利相变,而且能够稳定材料结构,从而有效提升再生高镍材料的循环稳定性(1 C电流密度下循环100圈的容量保持率高达95.7%).因此,本研究不仅揭示了废旧锂电池回收过程中氟的迁移转化行为,而且可控再生制备了高性能氟掺杂高镍LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)正极材料,为废旧锂离子电池回收过程中氟的调控提供了理论依据.